LIBRARY OF CONGRESS. 

fijap. H?* ©opjjrigJji f a 

Shelf .J±2J& 



UNITED STATES OF AMERICA. 



Outlines of Forestry; 



OR, 



THE ELEMENTARY PRINCIPLES 

UNDERLYING THE SCIENCE 

OF FORESTRY. 



BEING A SERIES OF PRIMERS OF FORESTRY. 



BY 

EDWIN J. HOUSTON, A.M., 

MEMBER OF THE PENNSYLVANIA FORESTRY ASSOCIATION, PROFESSOR OF PHYSICS 
IN THE FRANKLIN INSTITUTE OF THE STATE OF PENNSYLVANIA, PRO- 
FESSOR OF NATURAL PHILOSOPHY AND PHYSICAL GEOGRAPHY IN 
THE CENTRAL HIGH SCHOOL OF PHILADELPHIA, ETC., ETC. 



\ J * 

J&Q14 1 

HILADELPHIA: * 



p: 

J. B. LIPPINCOTT COMPANY. 
1893. 



Copyright, 1893, 

BY 

J. B. Lippincott Company. 



PR.NTEO BY J. B. L.PP.NCOTT COMPANY, PH.LADELPH.A. 






PREFACE. 



"When from any cause a necessity exists in any 
country for the removal of its forests from ex- 
tended areas, unless care be taken as to the man- 
ner in which such removal is made, and some 
parts are left wooded, irreparable injuries will 
inevitably follow. 

In the United States, where the enormous in- 
crease in population has resulted in the removal 
of the forests from extended areas, such intelli- 
gence and care have unfortunately, in most cases, 
not been exercised. The timber lands have gen- 
erally been purchased at figures based almost 
entirely on the value of the standing wood. The 
trees have been cut down in a reckless manner, 
and fires, carelessly started, have often been left 
indifferently to burn themselves out. Eo attempts 
have been made to protect the soil that has been 
denuded of its natural protective covering by the 
axe or the fire. Before the forest has been 
made to yield its entire harvest, the greed of the 



4 PREFACE. 

speculator has too often led him to abandon to the 
destructive action of the elements the area he has 
thus despoiled, in order to seek another, as yet 
unbroken, forest area. 

Instead of carefully removing some of the trees 
from the forest, and leaving the area in such a 
condition as to enable it to produce a new growth, 
in the United States it has too frequently been 
the case that the virgin forest is thoughtlessly 
attacked, its best trees cut down in so careless a 
manner that the harvested crop amounts to, per- 
haps, but a third, or even less, of the total growth, 
and the remaining part abandoned to certain 
destruction by the elements. 

The irreparable loss caused by such greed should 
be prevented by the enactment of judicious penal 
laws. 

It is often very difficult to persuade the general 
public that evil results following any course of 
action, which do not come immediately, are not 
thereby prevented from coming eventually. Be- 
cause the evil day draws not nigh quickly, there 
is a tendency to believe that it will never come at 
all. 

An attempt has been made in the " Outlines of 
Forestry" to point out to the general public, in 



PREFACE. 5 

simple, non-technical language, the character of 
the effects, both on the general climate- of a coun- 
try and on the distribution of its rainfall, which 
inexorably follow the unsystematic removal of its 
forests. 

It is only necessary to give the public some little 
insight into the effects produced by the destruction 
of the forest to arouse it to a conviction of the 
necessity for the existence of "Forestry Associa- 
tions," for the enactment of laws regulating the 
manner in which the forests shall be removed, 
and for the setting aside of certain districts on 
which forests shall be perpetually maintained. 

In order to enable the readers of this little book 
to carry their reading beyond the elementary prin- 
ciples which it discloses, appropriate extracts, taken 
from standard authors, and published by permis- 
sion of the authors or publishers, have been added 
at the end of each primer. In all cases the exact 
title of the book has been given, as well as the 
names of its publishers. 

For general aid in remembering the princi- 
ples discussed in each primer, a concise review 
has been given at the close of the book in the 
form of a primer of primers. 

The author has not hesitated to consult freely 
l* 



6 PREFACE. 

all standard authorities in matters pertaining to 
the general subject of forestry. 

There have been added to the book, in the shape 
of an appendix, lists of trees suitable for planting 
in different sections of the United States, as fur- 
nished by eminent authorities on the subject. 

The author desires to express his thanks to the 
gentlemen who have responded to his circular 
letter of inquiry as to lists of trees suitable for 
replanting in various sections of the United States, 
and to his friend Professor Charles S. Dolley for 
revision of the manuscript of this book. 

Edwin J. Houston. 

Central High School, Philadelphia, Pa., 
January, 1893. 



CONTENTS 



PA.GB 

I. — Forestry 9 

II. — Conditions Necessary for the Growth of 

Plants 20 

III.— The Wide Distribution of Plant Germs . 32 
IV. — Conditions Necessary for the Growth of 

Trees 42 

Y. — The Formation of Soil 50 

VI. — The Inanimate Enemies of the Forest . . 61 

VII. — The Animate Enemies of the Forest ... 71 

VIII. — The Destruction of the Forest 81 

IX.— The Earth's Ocean of Vapor 90 

X.— Eain 100 

XI.— Drainage 109 

XII.— Climate 119 

XIII. — Climate as Influenced by the Presence of 

the Forest 127 

XIV. — Purification of the Atmosphere 140 

XV.— Hail . 147 

XVI.— Reforestation and Tree-Planting .... 155 

XVII.— The Balance of Nature 164 

XVIII.— Primer of Primers 177 

Appendix 209 

Index 245 

7 



OUTLINES OF FORESTRY. 



I. FORESTRY. 



The science of forestry not only treats of the 
care and preservation of those parts of the earth 
that are covered with trees, hut also of the means 
best suited to the replanting of the areas from 
which the trees have been removed. 

If nature is let alone she will cover any por- 
tion of the earth where vegetable life is possible 
with the particular kind of vegetation best fitted 
to grow under the existing conditions of soil, heat, 
light, and moisture. 

Nature will, therefore, cover with forest all por- 
tions of the earth where forests are best fitted to 
exist. 

It may then be asked, on what does the science 
of forestry rest ? "Why not leave nature alone ? 
Such questions arise from a misunderstanding of 
what forestry endeavors to accomplish. Forestry 



10 OUTLINES OF FORESTRY. 

does not aim to oppose nature, but simply to aid 
her. It endeavors to make use of the conditions 
naturally existing in any locality that are favorable 
to the continued growth of trees, and to oppose 
or hold in check conditions unfavorable to such 
growth. 

The following considerations will suffice to show 
the necessity for the existence of Forestry Associa- 
tions, and the enactment of strict laws for the care 
and preservation of the rapidly decreasing forest 
areas of the earth. The North Temperate zone, 
the cradle of the human race, possesses the densest 
civilized population. This zone was originally 
covered by extensive forests, and is still heavily 
wooded over extended areas. 

Civilized man, however, cannot continue a 
dweller in the forest. It is true that in sparsely 
settled districts no necessity exists for the removal 
of the entire forest ; but, as the density of popula- 
tion increases, the demands made on the forest 
increase. Such demands will, therefore, increase 
rather than decrease in the near future. Hence 
the necessity for the existence of Forestry Associa- 
tions and the enactment of Forestry Laws. 

The demands made on the forest by civilized 
man are either — 



FORESTRY. 



11 



1. For the area on which the forest stands, or 

2. For some of the products of the forest, such 
as wood for building purposes or fuel, or bark for 
the tannery. 

The demands for the areas on which the forests 
stand are made either for the purpose of increas- 
ing the extent of the agricultural areas, or for the 
building of ordinary roads or railroads. 

"We may tabulate these demands as follows : 







' 1. 


For land to he cultivated for 




1. Area on 
which it ■ 




ordinary farm products. 




stands. 


2. 


For the construction of ordi- 






- 


nary roads or railroads. 


Encroachment 








on the forest 








for — 




f 1. 


Fuel. 






2. 


Charcoal. 




2. For its 
products. 


3. 
4. 
5. 
6. 


Building purposes generally. 
Fences. 
Kailroad ties. 
Telegraph poles. 






7. 
8. 


Mining purposes. 
Bark for tanneries. 






. 9. 


Turpentine, rosin. 



When the forests are removed for the area on 
which the trees stand, the destruction is necessarily 
complete. 

Where the removal is for agricultural purposes, 



12 OUTLINES OF FORESTRY. 

the destruction should not be complete. The prin- 
ciples of forestry teach that the truest economy 
will permit certain tracts to remain covered with 
trees; for the ultimate gain to the farmer from 
such a course will be greatly in excess of the 
sums paid for rental, or the interest-charges on 
the land that is not directly productive in ordi- 
nary farm products. 

The areas required to be taken from the forests 
for agricultural purposes necessarily greatly ex- 
ceed those required for the location of ordinary 
roads or railroads. The damage done indirectly 
to the forest, however, by the location of new 
roads, especially railroads, is often greater than by 
the location of new farming-lands, since the loca- 
tion of new roads greatly increases the liability to 
destructive fires, and also opens up extensive tracts 
of yet unmolested forest to the greed of the lum- 
berman, or to the indifference of the railroad 
authorities or of the travelling public. 

Besides this, an area taken for agricultural pur- 
poses is, to a certain extent, protected from the 
loss of its soil by a covering of vegetation. Dur- 
ing the construction and operation of a road-bed, 
much of the adjoining land is often needlessly 
destroyed by being thoughtlessly left for floods 



FORESTRY. 13 

to work irreparable damage by the removal of 
the soil. 

It is for the purpose of regulating the necessary 
removal of the forest, and for pointing out the 
manner in which the products of the forest can 
be most advantageously harvested, that Forestry 
Associations and Forestry Laws are so imperatively 
demanded. 

In order to intelligently protect forest areas, 
and thus aid rather than oppose nature in main- 
taining them, the principles underlying the growth 
of trees, the conditions of heat, light, and moisture, 
or, in general, the conditions of climate best suited 
to continue such growth, must be carefully studied. 
The natural influences or conditions which oppose 
the growth of trees must be ascertained, and, 
where possible, checked ; the enemies of the forest 
recognized, and the best means taken to hold them 
in check. In other words, forestry must assume the 
position of an exact science, in order to call intelli- 
gently for the passage of laws intended for insuring 
the growth and reproduction of the earth's forests. 

It is a mistaken idea that forestry endeavors to 
preserve intact the virgin forests of the earth. 
This is by no means the intent of intelligent for- 
estry. 

2 



14 OUTLINES OF FORESTRY. 

The wood and other products of the forest 
form an important part of the resources of a 
country. Man is as much entitled to the harvests 
of the woods as to the harvests of the fields. 
Forestry endeavors to point out the best ways in 
which forest crops maybe harvested without detri- 
ment to the subsequent crops, and without causing 
the ultimate destruction of the forest. 

Since it is manifestly impossible to preserve 
forests on all parts of the earth's surface where 
forests can naturally grow, it should be the duty 
and care of every community to set aside certain 
portions where forests shall be perpetually main- 
tained ; or, if already deforested, shall be replanted 
or reforested. Such preserves were originally 
maintained by the arbitrary will of the sovereign 
lord of the country, for the good of a few, in 
order to insure royal hunting-grounds. They 
should now be maintained, by the will of the 
people, for the good of the many. 

The parts best suited for the perpetual mainte- 
nance of forests will necessarily vary in different 
regions. 

In agricultural districts, certain areas should 
invariably be set aside on which trees shall be 
perpetually preserved; for true economy requires 



FORESTRY. 15 

the maintenance of some timber on nearly all 
farm-land. 

These areas will, perhaps, in the majority of 
cases be found as follows, — viz. : 

1. On poor or thin soils where no other crops 
will thrive. 

2. In damp places where no other crops will 
thrive. 

3. On the borders of rivers or other streams. 

4. On mountain slopes, hill-tops, or other 
elevations. 

It can be shown, generally, that the areas which 
can be most profitably set aside for the mainte- 
nance of perpetual forests are situated, for the 
greater part, in the mountainous districts of the 
earth, the natural home of the forest. 

As will hereafter be shown, the forests should 
especially be preserved on mountain slopes, for the 
following reasons : 

1. Because the rain falls more frequently and 
in greater quantity in the mountainous districts 
of the earth than elsewhere. The. cold mountain 
slopes, chilling the air, cause it to deposit its sur- 
plus moisture, in no matter from what direction 
the winds may come. 

2. Because the principal rivers of the earth 



16 OUTLINES OF FORESTRY. 

are born in the mountainous districts, and, if the 
forests are removed, the rain which falls drains so 
rapidly from the earth's surface that the soil 
that took a long time to form by the gradual 
disintegration of the igneous rocks, and slowly 
accumulated its vegetable mould from the growth 
and subsequent decay of thousands of generations 
of plants, is lost to the highlands, only to becjome 
a source of damage to the lowlands. 

3. Because the rapid drainage of the mountain 
slopes on the removal of their forests will result in 
dangerous floods during times of rain. 

4. Because the failure of so great a part of 
the rain-water to sink into the ground and fill the 
reservoirs of the springs will cause such springs 
to more readily dry up shortly after the appear- 
ance of drought. 

5. Because the mountain slopes, when de- 
prived of their forests, become excessively hot 
during the day, and excessively cold during the 
night, and thus tend to sensibly alter the climate 
of the country. 

6. Because such marked differences in tem- 
perature tend to increase the number and severity 
of destructive hail-storms. 

7. Because the removal of the forests tends to 



FORESTRY. 17 

increase the liability of occurrence of early frosts 
in the neighboring agricultural districts. 

8. Because the removal of the forests will be 
attended by marked changes in the relative quan- 
tity of moisture in the air at different times of the 
year. 

B. E. Fernow, Chief of the Department of For- 
estry in the United States Department of Agricul- 
ture, in a paper entitled " What is Forestry V * 
says, on page 15 : 

" Forestry in a wooded country means harvesting the wood 
crop in such a manner that the forest will produce itself in 
the same, if not in superior, composition of kinds. Beproduc- 
tion, then, is the aim of the forest manager, and the difference 
between the work of the lumberman and that of the forester 
consists mainly in this : that the forester cuts his trees with a 
view of securing valuable reproduction, while the lumber- 
man cuts without this view, or at least without the knowledge 
as to how this reproduction can be secured and directed at 
will. The efficient forest manager requires no tool other than 
the axe and the saw, — the planing-tools being only needed to 
correct his mistakes, — but he sees them differently from the 
lumberman." 

* Reprinted, by permission, from " What is Forestry ?" by 
B. E. Fernow, Washington, Government Printing- Office, 1891. 
b 2* 



18 OUTLINES OF FORESTRY. 

The true position which forestry takes in the 
United States is thus forcibly expressed in the 
Annual Eeport of the New York Forest Commis- 
sion, for the year ending December 31, 1890,* on 
page 91, as follows : 

"A misunderstanding has prevailed to some extent with 
regard to the attitude of forestry towards the lumber interests 
of private owners. It is, however, generally misunderstood, 
now, that the true interests of the lumbermen are not incom- 
patible with forest preservation, and it has been declared to 
be one of the objects of the forestry movement in this country 
'To harmonize the interests of the lumberman and the for- 
ester, and to devise for the lumbering interest such protection 
as is not given at the cost of the forests.' Forestry is not 
opposed to having trees cut down in the proper way. They 
must be cut to supply the world with timber. They furnish 
the material for shelter to mankind, and contribute to render 
the houses of men comfortable and beautiful by providing 
fuel and decorations. It is needless to point out here the 
manifold purposes for which wood is needed, and how largely 
it enters into our industries and arts, contributes to our con- 
venience and pleasure, and becomes a necessity of our daily 
lives. Civilization could hardly exist without it. It is from 
trees, and from trees only, that our needs for wood are supplied 

* Keprinted, by permission, from Annual Eeport of the 
New York Forest Commission, for the year ending Decem- 
ber 31, 1890. Albany : James B. Lyon, State Printer, 1891. 
Pp. 317. 



FORESTRY. 19 

through the timber-dealer and lumberman. It is not the ex- 
ercise of their vocation, but their frequent abuse of it, that 
calls for criticism, — a distinction that has not always been 
made by the critics. Estimates show that thirty billion feet 
are required annually in this country for building and manu- 
facturing purposes alone, leaving the fuel question out of con- 
sideration. It is the unwise, improvident, stupid method, or 
want of method, by which the cutting has heretofore too often 
been done, that is deplored. Under the old practice the 
forests have rapidly disappeared, and, if it continues, in a few 
years none will be left. The lumberman will have ruined his 
own business, as there will be no forests to furnish him with 
his stock in trade. It is the purpose of forestry to point out 
to the lumberman the true methods of exercising his own 
profession, which will provide him material for the future, as 
well as the present, by maintaining permanent forests through 
a succession of crops." 



20 OUTLINES OF FORESTRY. 



II. CONDITIONS NECESSARY FOR THE 
GROWTH OF PLANTS. 

Extended scientific research has established the 
fact that all forms of life, whether of the animal 
or the plant, can, at their earliest stages, be traced 
to a minute germ-cell filled with a more or less 
transparent substance called protoplasm, and con- 
taining a dark, opaque spot called the nucleus. 
Unless this germ-cell exists, plant or animal life is 
impossible. 

Although cases exist where there has been no 
apparent evidence of the presence of a germ or 
seed, yet such germ or seed must have existed, 
and was derived from a plant of exactly the same 
character as that which such seed will produce 
when called into active and matured growth. 

Under peculiar circumstances, plant or animal 
germs possess wonderful vitality, and may remain 
in a dormant state for a very long time, only 
beginning to grow when exposed to the conditions 
necessary for growth. 

In order that any form of plant life may exist 



CONDITIONS FOR THE GROWTH OF PLANTS. 21 

on the earth, the following conditions are neces- 
sary : 

1. The germ or seed from which the plant 
grows. 

The germ or seed in all cases comes directly 
from a plant similar to that which is produced 
when the seed sprouts or germinates, and attains 
its full growth. 

2. The cradle where the plant is horn. 

The plant's cradle is the soil. In the soil the 
plant spreads its roots, and from it obtains, in 
great part, the materials necessary for nourish- 
ment and growth. 

Cases exist where the plant finds its cradle in 
the air or in the water. These need not, however, 
be considered in this connection. 

3. The sunshine and the heatshine, which awaken 
the sleeping germ and call it into activity ; or, in 
other words, the light and heat which are so 
essential to a plant's growth. 

4. The nourishment, or the food which the 
plant takes into its structure and assimilates, and 
thus causes it to become a part of itself. 

The processes by which a plant causes different 
materials taken from the soil in which it grows, 
or from the air around it, to become a part of 



22 OUTLINES OF FORESTRY. 

itself, is called assimilation. At the commence- 
ment of its life the plant gets its nourishment 
from the protoplasm surrounding the nucleus. It 
is not long, however, before it exhausts this stock 
of food, and it must then get all its nourishment 
either from the soil or from the atmosphere ; or, 
in other words, from outside the seed. 

This latter nourishment of the plant comes 
from a variety of materials, derived either from 
the air or from the ground, the most important 
of which are as follows : 

1. Moisture. 

This moisture is mainly taken up by the roots 
of the plant from the soil; but it is, in some 
cases, absorbed directly from the air by the leaves. 

2. Carbonic acid. 

Carbonic acid is a gaseous substance, formed of 
carbon combined with an invisible gas called oxy- 
gen. The carbonic acid is absorbed by the leaves 
of the plant, and, in the presence of sunshine, is 
broken up into carbon and oxygen. The oxygen 
is given off from the surfaces of the leaves, and 
the carbon is retained by the plant to form its 
woody fibre. In the case of large vegetable forms 
like forest-trees, the amount of carbonic acid taken 
from the air and converted into woody fibre must 



CONDITIONS FOR THE GROWTH OF PLANTS. 23 

be very great. A certain amount of oxygen, how- 
ever, must be present in the air, to permit the 
continued growth of the plant ; for most plants will 
not grow in an atmosphere of pure carbonic acid gas. 

The hydrogen needed for the plant's growth is 
derived from the decomposition of the water asso- 
ciated with the carbonic acid; the result is that 
the plant retains the carbon and the hydrogen, and 
throws out the oxygen into the atmosphere. 

3. Mineral matters taken from the soil. 

The tissues of the plant contain various kinds 
of mineral substances which are taken directly 
from the soil. For the proper growth of the 
plant, the soil must contain these particular min- 
eral substances in the condition or state in which 
they can be readily taken up or assimilated by the 
plant. 

The above conditions — viz., the germ, the cradle, 
the sun's light and heat, and some form of solid 
and liquid food — are not of equal importance to 
the growth of the plant. 

The presence of the germ or seed is, of course, 
of the greatest importance, since without it no 
plant can grow. 

The sunshine and the heat may, perhaps, be 
considered as next in importance to the growth 



24 OUTLINES OF FORESTRY. 

of the plant. Heat and light are to be found in 
practically all parts of the earth. They differ, 
however, in amount, in different regions of the 
earth, and such differences cause the differences 
that are noticed in the plants that grow in dif- 
ferent regions. 

Even in the same region, differences in the light 
and heat cause differences in the plant's growth, 
as may be noticed in almost any forest region. 

The plants that form the undergrowth of those 
portions of the forest where the light is more 
thoroughly shut out are markedly different from 
those appearing in the clearings, where the light 
and heat have full access to the soil. 

The nourishment of the plant comes next in 
importance. The quantity of carbonic acid found 
in the air is practically the same in all parts of the 
earth. The quantity of moisture in the air differs 
very greatly in different parts of the earth, and 
on this difference, together with the difference of 
temperature, depends the differences observed in 
the plants of various regions. 

The liquid nourishment of the plant in the 
shape of water is of so great importance to the 
growth of the plant, that the character of the 
rain-fall in any country will, to a marked ex- 



CONDITIONS FOR THE GROWTH OF PLANTS. 25 

tent, determine the character of the flora' of that 
country. 

The soil is, perhaps, the least important of the 
conditions required for plant growth. 

This statement is at first thought so much at 
variance with the generally received opinion as to 
need an explanation. 

"Where a particular kind of plant is to be grown, 
the character of the soil, probably, stands next in 
importance to the presence of the germ or seed ; 
for each plant thrives best in a particular kind of 
soil. The variety of plants that exist, however, 
is so great that, given almost any kind of soil, 
together with certain conditions of heat, light, 
and moisture, such soil will be found to be best 
suited for the growth of some particular kind of 
plant. In other words, if the proper conditions 
of moisture, heat, and light are present, and the 
germ is present, vegetation will appear in almost 
any region. 

Nature has generously scattered the germs of 
various forms of plant life nearly all over the 
earth's surface. Therefore, if unmolested by man, 
she will, in most cases, maintain on such surfaces 
the kind of plant forms or plant growths best 
suited to grow naturally. 



26 OUTLINES OF FORESTRY. 

There, therefore, will be found in every section 
of country a plant growth or plant life peculiar 
to, or naturally belonging to, such a section of 
country. Each section of country possesses, so 
to speak, a nationality in its plants, or, in other 
words, there lives in each section of country a 
particular nation of plants. Such a nation of 
plants, or the plants peculiar to a particular sec- 
tion of country, is called its flora. 

Since heat, light, and moisture are, next to the 
presence of the plant germ, the most important 
things for plant growth, there will necessarily 
exist in different parts of the earth a flora that will 
vary according to the differences that exist in the 
distribution of heat, light, and moisture over such 
part of the earth's surface. 

The heat, light, and moisture are greater in 
amount at the equator than at any other portion 
of the earth's surface. Therefore, the vegetation 
is more luxuriant, or possesses a greater diversity 
of forms, here than at any other part of the sur- 
face. As we pass from the equator towards the 
poles, the decrease in the heat, light, and moisture 
causes a corresponding decrease in the variety and 
luxuriance of vegetable life. 

In passing from the base to the summit of a 



CONDITIONS FOR THE GROWTH OF PLANTS. 27 

high tropical mountain, the same differences in 
the variety and luxuriance of plant life are noticed 
that are seen in going from the equator to the 
poles. This is due mainly to the distribution of 
the heat and moisture. 

The planting of a germ or seed in any soil will 
not result in its continued growth, unless the con- 
ditions of heat, light, and moisture are practically 
the same as those in which the plant from which 
such germ or seed was derived required for its 
existence. 

Trees planted in a particular locality may, there- 
fore, fail to grow in such locality, from want of 
the proper conditions of heat, light, and moisture. 

In all regions where forests can grow naturally, 
wherever practicable, they should be permitted to 
grow, since, as will be shown, the continued ex- 
istence of forests on certain portions of the earth 
is necessary for insuring that balance of nature on 
which the comfortable existence of man depends. 

Guyot, on page 188 in his " Earth and Man," * 

* " The Earth and Man," lecture on Comparative Physi- 
cal Geography in its Eelation to the History of Mankind, by 
Arnold Guyot, Professor of Physical Geography and History 
at Neufchatel, Switzerland. Boston : Gould, Kendall & Lin- 
coln, 1849. 



28 OUTLINES OF FORESTRY. 

thus refers to the conditions favorable to luxuriant 
vegetable growth : 

"The warm and the moist — these are the most favorable 
conditions for the production of an exuberant vegetation. 
Now, the vegetable covering is nowhere so general, the vege- 
tation so predominant, as in the two Americas. Behold, 
under the same parallel where Africa presents only parched 
table-lands, those boundless virgin forests of the basin of the 
Amazon, those selvas, almost unbroken over a length of more 
than fifteen hundred miles, forming the most gigantic wilder- 
ness of this kind that exists in any continent. And what 
vigor, what luxuriance of vegetation ! The palm-trees, with 
their slender forms, calling to mind that of America itself, 
boldly uplifted their heads one hundred and fifty or two hun- 
dred feet above the ground, and domineer over all the other 
trees of these wilds, by their height, by their number, and by 
the majesty of their foliage. Innumerable shrubs and trees 
of smaller height fill up the space that separates their trunks ; 
climbing plants, woody- stemmed, twining lianos, infinitely 
varied, surround them both with their flexible branches, dis- 
play their own flowers upon the foliage, and combine them in 
a solid mass of vegetation, impenetrable to man, which the 
axe alone can break through with success. On the bosom of 
their peaceful waters swims the Victoria, the elegant rival of 
the Rafflesia, that odorous and gigantic water-lily, whose white 
and rosy corolla, fifteen inches in diameter, rises with a daz- 
zling brilliancy from the midst of a train of immense leaves, 
softly spread upon the waves, a single one covering a space of 
six feet in width. The rivers, rolling their tranquil waters 



CONDITIONS FOR THE GROWTH OF PLANTS. 29 

under verdurous domes, in the bosom of these vast wilds, are 
the only paths that nature has opened to the scattered inhabi- 
tants of these rich solitudes. Elsewhere, in Mexico and Yu- 
catan, an invading vegetation permits not even the works of 
man to exist ; and the monuments of a civilization compara- 
tively ancient, which the antiquary goes to investigate with 
care, are soon changed into a mountain of verdure, or demol- 
ished, stone after stone, by the plants piercing into their 
chinks, pushing aside with vigor, and breaking with irresisti- 
ble force, all the obstacles that oppose their rapid growth." 

The author, in his " Elements of Physical Geog- 
raphy," * page 119, thus refers to the growth of 
living matter : 

" All life, whether vegetable or animal, consists of various 
groupings of cells, or approximately spherical masses, con- 
sisting of a peculiar form of a jelly-like matter called proto- 
plasm, composed of various complex combinations of carbon, 
hydrogen, oxygen, and sulphur, called proteids. At its begin- 
ning all life consists of a minute germ- cell, filled with more 
or less transparent protoplasm, and containing a darker 
opaque spot called the nucleus. Examined by a sufficiently 
powerful glass, all living protoplasm is seen to be in constant 
motion, currents passing through the different parts in some- 
what definite directions. 

* Keprinted, by permission, from " The Elements of Physical 
Geography, for the Use of Schools, Academies, and Colleges." 
By Edwin J. Houston, A.M. Eldredge & Brother, No. 17 
North Seventh Street, Philadelphia. 1891. Pp. 272. 

3* 



30 OUTLINES OF FORESTRY. 

"As the germ-cell develops in all the higher forms of life, it 
multiplies, and various organs appear, peculiar to the form of 
life from which the germ-cell was derived. All living bodies 
contain organs, and living matter is therefore sometimes called 
organic matter, to distinguish it from non-living or inorganic 
matter. 

"Science has not yet disclosed the nature of the change 
whereby non-living matter is converted into living protoplasm. 
To produce living matter, the intervention of already living 
matter is, so far as is known, absolutely necessary." 

Concerning the influence of climate on plant 
growth, Elisee Keclus, in his work, " The Ocean," * 
on page 361, says : 

" Each plant has its special domain, determined not only 
by the nature of the soil, but also by the various conditions 
of climate, temperature, light, moisture, the direction and 
force of winds, and of oceanic currents. During the course 
of ages the extent of this domain changes incessantly, accord- 
ing to the modifications which are produced in the world of 
air, and the limits of the region inhabited by the various 
species are dovetailed into one another in the most compli- 
cated manner. The flora indicates the climate ; but what is 
the climate itself, in the apparently contused mixture of 
phenomena which compose it ? The preponderating influence 

* Reprinted, by permission, from " The Ocean, Atmosphere, 
and Life," by Elisee Reclus. New York : Harper & Brothers, 
Publishers, Franklin Square. 1874. Pp. 534. 



CONDITIONS FOR THE GROWTH OF PLANTS. 31 

is naturally that of temperature ; nevertheless, we must not 
think, as many botanists did till very recently, that the limits 
of the zone of vegetation of each plant are marked on the 
continents by the insinuosities of the isothermal lines. In fact, 
as Charles Martins and Alphonse de Candolle remark, each 
plant requires for its germination and development a certain 
amount of temperature, differing according to the species. 
With some, life resumes its activity after the sleep of winter, 
when the thermometer marks three or five degrees above the 
freezing-point ; others need a heat of eighteen, twenty, and 
even twenty-five and thirty- five degrees, before taking the first 
step in their career of the year. Each species has, so to say, 
its particular thermometer, the zero of which corresponds to 
the degrees of temperature when the vegetating force awakens 
its germs. It is, therefore, impossible to indicate by such 
general climatal lines the limits of habitation for such or such 
species, since each one of them has for the commencement of 
its vital period a different starting-point." 



32 OUTLINES OF FORESTRY. 



III. THE WIDE DISTRIBUTION OF 
PLANT GERMS. 

In order that seed-time and harvest shall not 
fail on the earth, nature has distributed the seeds 
or germs of plant life with a liberal hand over 
all parts of the surface. Even amid the burning 
sands of the deserts and the eternal snows of the 
polar regions, myriad forms of plant germs exist. 

Nature has provided numerous ways for insuring 
the thorough scattering of these plant germs or 
seeds. 

Many forms of seeds are provided with delicate 
hair-like projections, or with wings, by means of 
which they are carried by the winds to great 
distances. Others are provided with projecting 
hooks or bristles, by means of which they catch 
in the fur of animals, or in the plumage of birds, 
and are thus carried into distant regions. 

Perhaps one of the most important of the 
means provided by nature for the distribution of 
plant germs, is that the seeds, which are swallowed 
whole by birds or other animals, subsequently pass 



THE WIDE DISTRIBUTION OF PLANT-GERMS. 33 

out of the animal uninjured by the process of 
digestion. By such means seeds are carried to 
distant parts of the earth. 

Man, either purposely or accidentally, scatters 
plants, germs, or seeds in far-distant countries. 
Not unfrequently some of the plants thus brought 
from one country to another find the conditions 
of soil and climate in their new home so favorable 
to growth as to completely drive out and exter- 
minate domestic species. 

Besides the means just mentioned for the scatter- 
ing of germs or seeds of plants, there are possibly 
others that have not yet been recognized. 

The germs or seeds of plants possess a singular 
vitality under certain conditions. The grains of 
corn or wheat found in the Egyptian mummies, in 
many cases, grew and bore fruit notwithstanding 
their centuries of rest. Such instances of the 
preservation of vitality are, perhaps, less wonder- 
ful when viewed in the light of the exceedingly 
dry climate in which the mummies were preserved. 
More curious instances are found in which the 
germs existed for a long time in the presence of 
an abundance of moisture, and did not grow as 
long as the heat and light alone were absent. 

The truth of the above statements is denied by 



34 OUTLINES OF FORESTRY. 

some, but that such experiments succeeded in 
some cases is undoubtedly true. 

For example, in densely-wooded countries, where 
the ground is thickly covered with trees, the light 
and heat of the sun are so thoroughly expended 
in maintaining such growth that no other forms 
of plant life occur. Let, however, some of the 
trees be removed, so that the light and heat of 
the sun may reach the ground, and the seeds that 
were there, possibly during the centuries that the 
forest covered it, at once spring into active life. 
Here all the conditions except sufficient light and 
heat were present, and yet the germs slumbered. 

That the Sahara desert was once, in certain 
portions, if not in all parts, well watered, is 
attested by the presence of the wadys, or deserted 
river- valleys. That the soil of the desert contains 
a liberal supply of numerous plant germs, is shown 
by the fact that, on the successful sinking of an 
artesian well, the appearance of the water is in- 
variably attended by the appearance of a flora 
often containing peculiar species of plants. Here 
the light, heat, and soil were all present, and yet 
the germs slumbered for want of moisture. 

The boring of artesian springs, or the digging 
of cellars or other excavations, by bringing to the 



THE WIDE DISTRIBUTION OF PLANT-GERMS. 35 

sun's light and heat soil which has been deprived 
of such sunlight and heat for unknown ages, in 
many — indeed, in most — cases is followed by the 
appearance of vegetation often containing species 
quite strange to that particular section of country. 

A curious story of such a case is told, which, if 
true, shows in a striking manner the wonderful 
vitality of certain seeds. In a given section of 
country, let us say in England, a farmer com- 
menced to dig a well. This act, so common in 
an agricultural district, attracted no particular 
attention until the depth of the still dry hole far 
exceeded that of most wells in the locality. The 
neighbors then began to speculate as to whether 
the farmer would eventually strike water, but 
when he continued without success, many of his 
neighbors began to quietly laugh at him. The 
farmer, however, persisted, and at last his per- 
sistency or stubbornness, whichever it may have 
been, was rewarded. 

After having dug through a considerable deposit 
of sand, which appeared very much like the sand 
of an ancient sea-beach, a water-logged stratum 
was reached from which gushed forth a copious 
supply of excellent water. So pleased was the 
farmer with the result of his labors, that he ar- 



36 OUTLINES OF FORESTRY. 

ranged the sand and other materials brought up 
from below in a form of a garden-plot around the 
mouth of the well. Strange plants soon appeared, 
and among them a tree, which, when sufficiently 
matured, proved to be an ancient form of beech- 
plum. Now, since it is universally recognized that 
no form of plant life appears without the presence 
of a germ similar to that which the plant will it- 
self produce, the germ of this ancient beech-plum 
was presumably preserved in the deep-seated strata 
for untold centuries, awaiting to be called into life 
by the genial warmth and light of the sun. 

The virgin soil of the prairies, where turned up 
by the plough of the settler, generally produces a 
vegetation different from that of the undisturbed 
soil. Even the tracks of the settlers' wagons dis- 
turb the soil sufficiently to be afterwards marked 
by a growth of plants quite distinct from those 
which cover the undisturbed portions. The seeds 
must have lain a long time below the surface, 
only springing into active life on exposure to the 
light and heat of the sun. 

The burning of a pine forest in the North Tem- 
perate Zone is almost invariably followed by a 
growth of scrub oak. What was the origin of 
the germs of these oaks ? They presumably ex- 



THE WIDE DISTRIBUTION OF PLANT-GERMS. 37 

isted in the ground, and, in some as yet unex- 
plained manner, were aroused into active life by 
the presence of the fire. 

In some parts of the United States the burning 
over of a region is almost invariab]y followed by 
a growth of what is very appropriately called fire- 
weed, the seeds of which appear to have been 
called into active life in some as yet unexplained 
manner, either by something added to the soil by 
the heat, or possibly by the heat of the fire itself. 

Cases are on record where earthquakes have 
brought up to the surface, soil which had probably 
been buried for ages, but which, on exposure to 
the light and heat of the sun, gave birth to strange 
forms of plant life. 

Possibly, in some of the cases mentioned, the 
germs of plant life have been carried to the locali- 
ties by one or another of the agencies already 
mentioned. In other cases, however, the germs 
appear to have existed in the soil, waiting to be 
called into life by the sun's light and heat. 

Nature, therefore, has taken care that the earth 
shall be covered with a vegetable carpet wherever 
man does not oppose her action. If left to work 
out her own course, she will cover the earth with 
a dress of such vegetable forms as are best suited 

4 



38 OUTLINES OF FORESTRY. 

to exist there naturally. If interfered with, to 
even a comparatively trifling degree, such changes 
may be produced in the soil, climate, or other 
conditions as will bring wide-spread destruction 
to widely separated sections of the country. 

Speaking of the vitality of seeds, Marsh, in his 
work entitled " The Earth as Modified by Human 
Action," * page 295, says : 

" When newly-cleared ground is burnt over in the United 
States, the ashes are hardly cold before they are covered with 
a crop of fire-weed, Senecio hieracifolius, a tall, herbaceous 
plant, very seldom seen growing under other circumstances, 
and often not to be found for a distance of many miles from 
the clearing. Its seeds, whether the fruit of an ancient vegeta- 
tion or newly sown by winds or birds, require either a quicken- 
ing by a heat which raises to a high point the temperature of 
the stratum where they lie buried, or a special pabulum fur- 
nished only by the combustion of the vegetable remains that 
cover the ground in the woods. 

"Earth brought up from wells or other excavations soon 
produces a harvest of plants often very unlike those of local 
flora, and Hayden informs us that on our great Western desert 
plains, wherever the earth is broken up, the wild sunflower 
(Helianthus) and others of the taller-growing plants, though 

* Reprinted, by permission, from " The Earth as Modified by 
Human Action," by George P. Marsh. New York : Scribner, 
Armstrong & Co., No. 654 Broadway, 1874. Pp. 656. 



THE WIDE DISTRIBUTION OF PLANT-GERMS. 39 

previously unknown in the vicinity, at once spring up, almost 
as if spontaneous generation had taken place." 

The wonderful vitality of certain seeds is thus 
referred to by Lindley in his " Botany," * on page 
358: 

" The action of seeds is confined to that phenomenon which 
occurs when the embryo which the seed contains is first called 
into life, and which is named germination. 

" If seeds are sown as soon as they are gathered, they gener- 
ally vegetate, at the latest, in the ensuing spring ; but, if they 
are dried first, it often happens that they will lie a whole year 
or more in the ground without altering. This character varies 
extremely in different species. The power of preserving their 
vitality is also variable : some will retain their germinating 
powers many years, in any latitude, and under almost any 
circumstances. Melon-seeds have been known to grow when 
forty-one years old, maize thirty years, rye forty years, the 
sensitive plant sixty years, kidney-beans one hundred years. 
Clover will come up from soil newly brought to the surface of 
the earth, in places in which no clover had been previously 
known to grow in the memory of man, and I have at this mo- 
ment three plants of raspberries before me, which have been 
raised in the garden of the Horticultural Society from seeds 
taken from the stomach of a man whose skeleton was found 

* " An Introduction to Botany," by John Lindley, Ph.D. 
London: Longman, Orme, Brown, Green, and Longmans. 
Third Edition, 1839. Pp. 594. 



40 OUTLINES OF FORESTRY. 

thirty feet below the surface of the earth, at the bottom of a 
barrow which was opened near Dorchester. He had been 
buried with some coins of the Emperor Hadrian, and it is 
therefore probable that the seeds were sixteen or seventeen 
hundred years old." 

" It has already been seen that under certain circumstances, 
the vitality of seeds may be preserved for a very considerable 
length of time ; but it is difficult to say what are the exact 
conditions under which this is effected. We learn from ex- 
periment that seeds will not germinate if placed in vacuo, or 
in an atmosphere of hydrogen, nitrogen, or carbonic acid ; but 
no such conditions exist in nature, and, therefore, it cannot 
be they which have occasionally preserved vegetable vitality 
in the embryo plant for many years. Perhaps the following 
remarks, in a work lately published by the Society for the 
Diffusion of Useful Knowledge, may throw some light on the 
subject: 

" It may, upon the whole, be inferred from the duration of 
seeds buried in the earth, and from other circumstances that 
the principal conditions are, 1, uniform temperature ; 2, mod- 
erate dryness ; 3, exclusion of light ; and it will be found 
that the success with which seeds are transported from foreign 
countries, in a living state, is in proportion to the care and 
skill with which these conditions are preserved. For exam- 
ple, seeds brought from India, round the Cape of Good Hope, 
rarely vegetate freely : in this case the double exposure to the 
heat of the equator, and the subsequent arrival of the seeds 
in cold latitudes, are probably the causes of their death ; for 
seeds brought overland from India, and therefore not exposed 
to such fluctuations of temperature, generally succeed. Others, 



THE WIDE DISTRIBUTION OF PLANT-GERMS. 41 

again, which cannot be conveyed with certainty if exposed to 
the air, will travel in safety for many months if buried in 
clay rammed hard in boxes : in this manner only can the 
seeds of the mango be brought alive from the West Indies ; 
and it was thus the principal part of the Araucania pines, now 
in England, were transported from Chile. It may therefore 
be well worth consideration, whether by some artificial con- 
trivance, in which these principles shall be kept in view, it 
may not be possible to reduce to something like certainty the 
preservation of seeds in long voyages, — such, for instance, as 
by surrounding them with many layers of non-conducting 
matter, as case over case of wood, or by ramming every other 
space, in such cases, with clay in a dry state." 



4* 



42 OUTLINES OF FORESTRY. 



IV. CONDITIONS NECESSARY FOR THE 
GROWTH OF TREES. 

If a soil exists in any locality, and certain con- 
ditions of light, heat, and moisture are present, 
the character of the vegetation that naturally 
grows in such a region will depend more on the 
peculiarities of the distribution of the heat, light, 
and moisture, than on the character of the soil 
itself. 

If moisture he entirely absent, or if it exists in 
such a form as ice or snow, in which it cannot be 
readily appropriated by plants, then that region 
must become a desert. 

Deserts occur either in dry, arid regions, or in 
the regions of perpetual snow of the polar zones, 
or on the higher mountain slopes. 

If the rainfall is absent during certain seasons of 
the year, but occurs during the rest of the year, — 
that is, if one part of the year is dry and the rest 
is wet, — the vegetable forms, which die or disap- 
pear at the beginning of the dry season, reappear 
at the beginning of the wet season. Areas of the 



CONDITIONS FOR THE GROWTH OF TREES. 43 

earth possessing this character of vegetation are 
called steppe regions. 

When the rainfall is not very great in amount, 
but is fairly well distributed throughout the year, 
so that the rain is never absent for a very long 
time, regions called meadows or prairies occur. 

If there is an abundance of moisture at nearly all 
times throughout the year, so that such moisture 
is absent for no very long time, then the country 
may be covered by trees. Such areas are called 
forests. 

Forests cannot exist in the temperate zones of 
the earth in localities where, during the time of 
the trees' active growth, a very long interval exists 
during which no rain falls. "While the active 
growth of the trees is temporarily suspended, as 
during the winter, this necessity for liquid nour- 
ishment, of course, no longer exists. 

The reason forests cannot grow except where 
moisture is present during nearly all the time the 
plants are growing, will be easily understood from 
the following considerations : 

Suppose a soil exists in any section of country, 
and such soil contains germs of practically all 
species of plant life. When such a soil is sub- 
mitted to the action of light, heat, and moisture, 



44 OUTLINES OF FORESTRY. 

most of these germs will be called into active 
growth, and various forms of plant life will begin 
their existence. 

Suppose this particular section be a region 
where, for several months of the year, no rain 
falls, and whose soil, as is generally the case, 
rapidly becomes dry. During the dry season all 
forms of plant life will die from want of proper 
nourishment 

On the reappearance of the wet season, only 
those forms of plant life will appear that have 
been able, during the brief time of the wet season, 
to reach their full maturity and produce their fruit 
or seeds, and so supply the germs necessary for a 
new growth. Such forms as trees, which, as is 
well known, require many years to mature their 
seed or fruit, will necessarily be unable to continue 
to grow naturally in such a region of country. 

Of course, it might easily happen that during 
the first wet season all the germs might not have 
been called into active life by the combined influ- 
ence of- the light and heat, so that on the next wet 
season such forms might again spring up naturally. 

But their continued existence, under these cir- 
cumstances, would be impossible from the absence 
of the new germs. 



CONDITIONS FOR THE GROWTH OF TREES. 45 

In any section of country where the rainfall is 
limited to certain periods of the year, only those 
plants can continue to grow that, during the time 
the rain continues and water is supplied to them, 
or during the time the plant is actually growing, 
can reach their maturity and develop their seeds, 
and thus supply new germs that shall be ready 
for the appearance of the next rainy season. 

For the growth of forests, both a certain depth 
of soil and, in general, a certain character of soil 
are necessary. This soil was slowly formed by the 
decomposition of the hard, igneous rocks that origi- 
nally formed the entire crust of the earth, and 
contains a quantity of vegetable mould or humus 
derived from many successive generations of plant. 

In the beginning, when the rocks' bare surfaces 
emerged from the universal oceans, forests could 
not grow even where the proper conditions of 
light, heat, and moisture were present, until such 
soil had been prepared for them. 

Extensive forests can exist naturally only in 
regions where suitable soil exists and where the 
rainfall during the time of growth is maintained 
with a certain approach towards regularity, so 
that the trees are then properly and continually 
supplied with liquid nourishment. 



46 OUTLINES OF FORESTRY. 

It is in the temperate regions of the earth and 
in some parts of the tropics that the great forest 
areas are to be found, since it is in these regions 
that the rain may fall at almost any time of day, 
and on almost any day of the year. 

There are, however, certain regions in the tropics 
where forests exist, although there are compara- 
tively extended periods during the growth of the 
trees when rain does not fall. Here, however, the 
air is very moist, and heavy dews take the place 
of rain, or the rich vegetable humus absorbs the 
vapor directly from the air; or, in some cases, 
though growth is not actually suspended, it is at 
least so markedly retarded that the decreased 
nourishment of the trees is less injurious. 

It is especially on the sides of mountains, where 
rain may fall in no matter from what direction the 
wind comes, or on the side of an island or conti- 
nent that receives the prevalent wind, that forests 
are to be found in nearly all portions of the earth's 
surface, provided the heat is sufficiently great and 
a suitable soil is present. These conditions of soil 
and temperature exist on nearly all mountain 
slopes outside the polar regions. 

The mountains may, therefore, be regarded as 
the natural home of the forests. The mountains 



CONDITIONS FOR THE GROWTH OF TREES. 47 

are also the natural birthplaces of the rivers. 
The preservation of the forests on the sides of 
mountains is necessary to insure such a drainage 
of the rainfall as will best preserve the uniform 
flow of the rivers and best prevent them from 
overflowing their banks in times of rain, or be- 
coming too shallow in times of drought. 

The preservation of the forests is necessary in 
certain portions of the lowlands to protect the 
crops from the direct action of winds that are 
either too hot or too cold. 

When it is necessary to cut down the forests for 
the sake of their timber, the areas on which they 
grew in all cases should be replanted, so that 
such areas may be able to yield continually suc- 
cessive crops of timber so necessary for man's 
needs. 

As to the necessity for an abundance of water 
well distributed throughout the year in order to 
insure the growth of trees, Guyot, in his " Earth 
and Man," * says, on page 189 : 



* " The Earth and Man : Lectures on Comparative Physical 
Geography in its Eelation to the History of Mankind/' by 
Arnold Guyot. Boston: Gould, Kendall & Lincoln, 59 
Washington Street, 1849. 



48 OUTLINES OF FORESTRY. 

" North America, in spite of its more continental climate, 
shares no less in this character of the New World. The 
beauty and the extent of the vast forests that cover its soil, 
the variety of the arborescent species composing them, the 
strong and lofty size of the trees which grow there, all these 
are too well known for me to stop and describe them. It is 
because to a more abundant irrigation this continent adds a 
soil slightly mountainous, almost everywhere fertile, securing 
it always an equal moisture, a more abundant harvest of all 
the vegetables useful to man." 

Concerning the growth of trees on mountain 
slopes, £lisee Keclus, in his work, " The Ocean," * 
says on page 383 : 

" The stages of vegetation have been studied with care on 
the slopes of many other mountains of temperate Europe, 
especially on the sides of the Ventoux, by M. Charles Martins ; 
but it is in the Alps, above all, that the most celebrated bota- 
nists of our country have made their comparative researches 
on the floras of the various altitudes. The limits of these 
floras vary, so far as we can understand, according to the form, 
exposure, and height of the mountains, the nature of the 
rocks, the moisture of the soil, and abundance of snow, and 
the meteorological conditions of the surrounding atmosphere. 
It is, therefore, impossible to give the precise figures on the 
whole of the Alpine masses, and the averages obtained by 

* Keprinted, by permission, from " The Ocean, Atmosphere, 
and Life," by Elisee Eeclus. New York : Harper & Brothers, 
Publishers, Franklin Square, 1874. Pp. 534. 



CONDITIONS FOR THE GROWTH OF TREES. 49 

savants have only a very general value. Without taking ac- 
count of the upper limits of cultivation, which varies singu- 
larly in the high valleys in proportion to the industry, intelli- 
gence, and social condition of the inhabitants, we may say 
that the vegetation of the plain hardly exceeds three thousand 
feet; above this height the slopes where man has not violently 
interfered to change the productions of the soil are naturally 
covered by vast forests. Still, the great trees gradually dimin- 
ish in height in proportion as we rise into a zone where the 
air is rarer and colder ; their wood becomes harder and more 
knotted ; and the hardy kinds, which venture not far from the 
region of the snows, end by creeping on the ground, as if to 
seek shelter between the stones. To the north of Switzerland, 
the beech does not exceed the height of four thousand feet, 
and the spruce-fir stops at six thousand feet. In the group of 
Monte Rosa, the same forest growth, which approaches most 
nearly to the zone of perpetual snow, ascends as far as six 
thousand two hundred feet on the northern slope ; while on 
the opposite side the larch, still hardier, attains its upper 
limit at seven thousand two hundred feet. Higher still we 
only find the fantastically twisted trunks of a few mugho pines, 
rhododendrons, willow-herbs, and juniper-trees ; then all vege- 
tation becomes more stunted, and is attached to the ground in 
order to escape the icy winds, and to allow of its being covered 
in winter with a protecting layer of snow up to the very edges 
of the glacier and the white surface of the snows." 



c d 



50 OUTLINES OF FORESTRY. 



V. THE FORMATION OF SOIL. 

The soil, in which the plant grows and which 
forms its cradle, is composed chiefly of mineral 
matters derived from the originally crystalline 
rocks which were formed by the gradual cooling 
of the earth's crust. The soil, however, also con- 
tains a small quantity of vegetable mould or 
humus, obtained by the growth and subsequent 
decay of successive generations of plants. 

Before soil can be formed, the hard crystalline 
rocks must be broken up, or, as it is technically 
called, disintegrated. 

This disintegration is effected to some slight 
degree by the roots of plants, but it is mainly 
brought about by the action, in one way or an- 
other, of water. 

Soils are divided by Gray into gravelly, sandy, 
clayey, calcareous, loamy, and peaty. 

Gravelly soils are such as have coarse pebbles 
or fragments of quartz, lime, or feldspar spread 
through more finely divided mineral matter. 

Sandy soils are usually formed of fine particles 



THE FORMATION OF SOIL. 51 

of quartz, associated with feldspar. Such soils 
generally contain some compound of iron. 

Clayey soils are formed from the decomposition 
of feldspathic rocks. They are impervious to 
water and harden on drying. 

Calcareous soils contain carbonate of lime in 
large amounts. 

Peaty soils are such as contain a large proportion 
of partially decayed vegetable matter. 

The soil is sometimes found resting in place, 
directly on top of the rocks from which it was 
derived. In such cases its various mineral ingre- 
dients can be traced directly to the decomposition 
of the underlying rocks. 

A section of such rock and soil will show the 
rock gradually passing from the loose soil into the 
hard and unchanged rock. 

In other cases the soil is found at a considerable 
distance from the locality in which it was originally 
formed, or in which the plants grew that produced 
its vegetable mould. 

The soil is carried from the rocks from which 
its mineral ingredients were derived either by the 
action of the winds or by the waters, though 
mainly by the latter, to distances which often reach 
thousands of miles. 



52 OUTLINES OF FORESTRY. 

"Where the soil remains directly on the surface of 
the rocks from which it was derived, it is interest- 
ing to trace the gradual changes that occur in 
passing downward from the loose soil to the hard, 
unchanged rock below. On top is the loose soil, 
with the admixture of vegetable humus so neces- 
sary to the growth of the higher forms of vege- 
table life. Under this is thoroughly broken-up 
rock, which contains less vegetable matter. Under 
this is coarser and less broken-up rock. Under 
this the rock is intact and merely softened by 
the agencies effecting the disintegration. Finally, 
lying under all, is the still untouched virgin rock. 

The principal agencies causing the disintegration 
of rocks are : 

1. The expansive force which sprouting or grow- 
ing vegetation exerts on the rock. 

2. The alternate expansions and contractions 
that attend the freezing and thawing of the water 
which flows into the crevices between the rocks, 
or sinks into their porous structure. 

3. The erosion or cutting power of water charged 
with suspended matter or sediment. 

4. The erosion or cutting of glaciers or masses 
of moving ice. 

5. The solvent power of water, especially when 



THE FORMATION OF SOIL. 53 

aided by the chemical action of such gases as 
oxygen and carbonic acid gas dissolved in the 
water. 

During the vigorous growth of any form of 
plant life the increase in the length and diameter 
of the roots will break up or disintegrate even the 
hardest of rocks. This action is especially effec- 
tive from the fact that in many cases the roots ex- 
tend for the greater part through crevices or cracks 
where the quantity of moisture is greater than 
elsewhere. 

The effects of alternate expansion and contrac- 
tion are limited to climates where the temperature 
occasionally falls below the freezing-point of water. 
The water sinking into the porous rocks, and fill- 
ing the crevices and cracks between them, expands 
on freezing and breaks the rock into fragments. 
These fragments are afterwards broken into smaller 
fragments, until the pieces are sufficiently small to 
be carried by the winds and waters to distant 
localities. 

The ability of running water charged with sus- 
pended mineral matter to cut or wear away hard 
rocks is very great. The moving water carries 
mechanically suspended in it minute fragments of 
such hard minerals as angular fragments of quartz 

5* 



54 OUTLINES OF FORESTRY. 

or pebbles. These act as planes, cutters, or chisels 
that gnaw, cut, or wear away even the hardest 
rock. This process is technically called erosion, 
and is of great aid in the formation of soil. 

There collects on the sides of mountains above 
the limit of perpetual snow an immense accumula- 
tion of snow, which, through gradual pressure, is 
converted into hard ice, and forms masses called 
glaciers. The glaciers slowly move or slip down 
the sides of the mountain. They receive the 
drainage of snow from the slopes of the valleys 
through which they move, just as rivers receive the 
drainage of liquid water. The glaciers carry with 
them considerable mineral matter, both in the 
shape of small rocks and large boulders. As the 
mass moves down the mountains, this mineral 
matter is pressed against the sides of the val- 
leys, or along the bottom of the bed through 
which it is moving, and cuts, grooves, or grinds 
the hard rocks, and thus aids in the production 
of soil. 

From its great solvent power, water is able to 
finally sink into what were originally impervious 
rocks, by gradually dissolving out the soluble 
portions of the rocks. In this way the rock is ren- 
dered rotten by the removal of the materials which 



THE FORMATION OF SOIL. 55 

formerly acted as a cement to bind its different 
ingredients together. "When charged with either 
oxygen or cabonic acid gas, derived generally 
directly from the air, the chemical action of these 
dissolved gases greatly aids the water in break- 
ing up, and thus rendering partly porous, even the 
hardest of the igneous rocks. 

Let us take, for example, some of the com- 
monest minerals of the igneous rocks, such as 
quartz, feldspar, and mica. 

None of these ingredients are very soluble in 
pure water ; but if the water contains oxygen and 
carbonic acid gas in solution, the feldspar will be 
gradually broken up, and the hard granites or 
gneisses, which form so large a portion of the 
igneous rocks, will be gradually disintegrated. 
From the feldspar will be derived the kaolins or 
clays, and the water percolating through them 
will be charged with a small quantity of potash, 
so necessary for the growth of plants. 

Limestones are readily disintegrated by water 
which contains carbonic acid in solution, and from 
such rocks are derived the calcareous matter so 
necessary to plant-growths. 

The carbonic acid dissolved in water sometimes 
acts to considerably change the character of the 



56 OUTLINES OF FORESTRY. 

soil, by effecting new combinations of its mineral 
constituents. 

Some soils possess the very valuable property of 
absorbing water vapor directly from the atmos- 
phere and condensing it in their pores. This 
property is exceedingly valuable during times of 
extended droughts, when a considerable quantity 
of vapor may be present in the air. Of all soils, 
those containing the greatest quantity of vegetable 
mould or humus possess this valuable property in 
the greatest degree. Clayey soils also possess it 
to a marked degree. 

Soils also possess the power of absorbing gases. 
Ordinarily, most soils contain of absorbed gases 
a smaller proportion of oxygen and more carbonic 
acid gas than the atmosphere. 

The ability of soils to absorb the sun's heat 
varies with their color; as a rule, dark-colored 
soils absorb the heat more rapidly than light- 
colored soils. 

Darwin has shown that in certain localities the 
common earthworm greatly aids in the formation 
and physical character of the soil by extensive bur- 
rowing and tunnelling. 

In all cases, however, the process by which the 
soil is formed is a gradual one ; and since there is 



THE FORMATION OF SOIL. 57 

necessarily mingled with such, finely hroken-up 
mineral matters a quantity of vegetable humus 
derived from the decay of successive generations 
of plants, its formation is rendered still more 
gradual. 

In wooded districts, where a carpet of decaying 
leaves covers a large part of the ground during 
most of the year, the water that soaks into such 
porous soil naturally contains a larger quantity 
of carbonic acid than would water that had not 
previously been passed through such matter. This 
dissolved carbonic acid, from its chemical action 
on the ingredients of the rock, greatly aids the 
water in forming new soil. 

Speaking of the loss of the vegetable mould, 
gained by the patient accumulation of different 
generations of plants through passing centuries, 
M. de Bouville, a Prefect of the lower Alps, in a 
report to the Government, quoted by Marsh on 
page 540 of " The Earth as Modified by Human 
Action," * writes as follows : 



* Eeprinted, by permission, from " The Earth as Modified 
by Human Action," by George P. Marsh. New York : Scrib- 
ner, Armstrong & Co., 654 Broadway, New York, 1874. Pp. 
656. 



58 OUTLINES OF FORESTRY. 

" It is certain that the productive mould of the Alps, swept 
off by the increasing violence of that curse of the mountains, 
the torrents, is daily diminishing with fearful rapidity. All 
our Alps are wholly, or in large proportion, bared of wood. 
Their soil, scorched by the sun of Provence, cut up by the 
hoofs of the sheep, which, not finding on the surface the grass 
they require for their sustenance, gnaw and scratch the ground 
in search of roots to satisfy their hunger, is periodically washed 
and carried off by melting snows and summer storms. 

" I will not dwell on the effects of the torrents. For sixty 
years they have been too often depicted to require to be farther 
discussed, but it is important to show that their ravages are 
daily extending the range of devastation. The bed of the 
Durance, which now in some places exceeds a mile and a 
quarter in width, and, at ordinary times, has a current of 
water less than eleven yards wide, shows something of the 
extent of the damage. Where, ten years ago, there were 
still woods and cultivated grounds to be seen, there is now 
but a vast torrent ; there is not one of our mountains which 
has not at least one torrent, and new ones are daily forming." 

The power of a glacier with its fragments of 
rocks to erode the valleys through which it passes 
is thus referred to by Le Conte, in his " Elements 
of Geology," * on page 51. 

* Eeprinted, by permission, from the " Elements of Ge- 
ology," by Joseph Le Conte, Professor of Geology and Natural 
History in the University of California. New York : D. 
Appleton & Co., 551 Broadway, 1878. Pp. 588. 



THE FORMATION OF SOIL. 59 

" When we consider the weight of glaciers and their un- 
yielding nature as compared with water, it is easy to see that 
their erosive power must be very great. This is increased 
immensely by fragments of stone of every conceivable size 
carried along between the glacier and its bed. These partly 
fall in at the sides and become jammed between the glacier 
and the confining rocks, partly fall into the crevasses and work 
their way to the bed, and partly are torn from the rocky bed 
itself. The effects of glacier erosion differ entirely from those 
of water : 1. Water, by virtue of its perfect fluidity, wears away 
the softer spots of the rock and leaves the harder standing in 
relief; while a glacier, like an unyielding rubber, grinds both 
hard and soft to one level. This, however, is not so absolutely 
true of glaciers as might be supposed. Glaciers, for reasons to 
be discussed hereafter, conform to large and gentle inequalities 
of their beds, though not to small ones, acting thus lik« a very 
stiffly viscous body. Thus, their beds are worn into very re- 
markable and characteristic smooth and rounded depressions 
and elevations called roches mouton'ees. Sometimes large and 
deep hollows are swept out by a glacier at some point where 
the rock is softer, or where the slope of the bed changes sud- 
denly from a greater to a less angle. If the glacier should 
subsequently retire, water accumulates in these excavations 
and forms lakelets. Such lakelets are common in old glacier 
beds." 

Geikie thus describes the formation of soil in 
his " Text-Book of Geology/' * on page 339 : 

* Eeprinted, by permission, from " Text-Book of Geology," 
by Archibald Geikie, LL.D., F.E.S, Director of the Geo- 



60 OUTLINES OF FORESTRY. 

" On level surfaces of rock the weathered crust may remain 
with comparatively little rearrangement until plants take root 
on it, and by their decay supply organic matter to the de- 
composed layer, which eventually becomes what we term 
* vegetable soil.' Animals also furnish a smaller proportion 
of organic ingredients. Though the character of the soil de- 
pends primarily upon the nature of the rock out of which it 
has been formed, its fertility arises in no small measure from 
the commingling of decayed animal and vegetable matter with 
decomposed rock. 

" A gradation may be traced from the soil downwards into 
what is termed the ' subsoil,' and thence into the rock under- 
neath. Between the soil and the subsoil a marked difference 
in colour is often observable, the former being yellow or brown, 
when the latter is blue, gray, red, or other colour of the rock 
beneath. This contrast, evidently due to the oxidation and 
hydration especially of the iron, extends downwards as far as 
the subsoil is opened up by the rootlets and fibres to the 
ready descent of rain-water. The yellowing of the soil may 
even be occasionally noticed around some stray rootlet which 
has struck down farther than the rest, below the general limit 
of the soil." 

logical Survey of Great Britain and Ireland, etc., etc. London : 
Macmillan & Co., 1882. Pp. 971. 



THE INANIMATE ENEMIES OF THE FOREST. 61 



VI. THE INANIMATE ENEMIES OF 
THE FOREST. 

Like other forms of animate nature, the forest 
is compelled to make a continual struggle for ex- 
istence. In order that it may continue to exist, 
the conditions requisite for its growth must be 
maintained, and the influences that oppose such 
growth must be held in check. 

The character of the vegetation that covers any 
region of the earth is dependent not only on the 
character of its soil, but also on the peculiarities 
of its climate ; such, for example, as the distribu- 
tion of the temperature throughout the year, the 
distribution of the moisture, etc. 

There is in the vegetable as in the animal world 
a veritable struggle for existence. Given a partic- 
ular character of soil and climate in any locality, 
the plants that will continue to grow in such 
locality will be those that are best fitted to exist 
there naturally. 

At first all forms may appear ; but some partic- 
ular form may be so much better suited to the 



62 OUTLINES OF FORESTRY. 

natural conditions of the locality, that it will grow* 
and multiply so rapidly as to choke out of exist- 
ence all other forms. Even such forms, however, 
will continue to exist only as long as the condi- 
tions continue favorable for their existence. 

The dependence of plant life on climatic condi- 
tions is, perhaps, more marked in the higher 
forms of the vegetable world. Trees may, in a 
certain sense, be regarded as of the highest type of 
plant life. They rigorously depend on conditions 
of soil and climate for their continued existence. 
It is true that when a forest is once formed, and its 
vigorous growth has almost completely shut out 
the light from the soil in which it is growing, that 
the numerous forms of vegetable life which lie 
ready to spring up, should the sun's rays find free 
access to them, are prevented from growing. Even 
if they did appear, and the climatic conditions 
remained as before, the same struggle for existence 
would again occur, and the same forest would in 
all probability finally be reproduced. If, however, 
the character of the soil be altered, or the climatic 
or other conditions be changed, the forests would 
either disappear or be replaced by trees of another 
character. 

The forest has many enemies that are ready at 



THE INANIMATE ENEMIES OF THE FOREST. 63 

all times to resist its growth, and even to sweep it 
out of existence. 

The soil is continually undergoing a small 
change in composition as the different growths of 
plants appear and disappear. 

The earth's climate is at present undergoing but 
very little change. In the geological past such 
changes were so far-reaching and severe that they 
were followed by pronounced changes in both the 
animal and plant life. The comparatively small 
changes that have occurred within historical time 
are, perhaps, rather to be regarded as some of the 
effects produced by the disappearance of certain 
forms of plant life, than as the causes of such 
disappearance. 

The exact balance of conditions that permit the 
continued existence of forests is so delicate, that 
causes, comparatively insignificant in themselves, 
may finally produce marked effects. 

The enemies of the forest may be divided into 
two classes : 

1. Inanimate. 

2. Animate. 

The principal inanimate enemies of the forest 
are : 
a. Fire. 



64 OUTLINES OF FORESTRY. 

b. "Winds. 

c. Floods. 

d. Avalanches. 

The principal animate enemies of the forest are : 

a. Plants. 

b. Animals. 

c. Man. 

Limiting our consideration, for the present, to 
the inanimate enemies of the forest, we will dis- 
cuse the manner in which each of these enemies 
tends to destroy the forest. 

Fire. — The destruction of the forest hy fire 
sometimes results finally in a more complete loss 
than hy any other cause. In case of the intelligent 
removal of the forest by the axe of the lumber- 
man, only the larger trees are cut down, and the 
smaller ones that are left, getting more heat, light, 
and nourishment, grow rapidly, and are, in turn, 
soon ready for removal by the axe, thus to give 
place to others. 

Fire, however, generally removes both great and 
small. 

While a fire may sometimes increase the growth 
of forests, as in the case of the pitch pine by the 
destruction of the less hardy forms of plant life, 
the destruction of the forest by fire, especially on 



THE INANIMATE ENEMIES OF THE FOREST. 65 

the slopes of mountains, is often so complete that 
before a new vegetation can appear, the rapid 
drainage of the slopes is attended by such a loss 
of the soil as to render such slopes unfit to repro- 
duce the forest trees for a period of time much 
longer than the life of the average man. 

Forest fires are generally kindled during the 
drier seasons of the year. Under these conditions 
the rain which subsequently falls is apt to carry 
oft' so much of the soil that, even should the trees 
again appear, the remaining soil would probably be 
insufficient in quantity to bring them to maturity. 

The causes of forest fires are to be found in 
camp-fires of the lumberman, the burning of 
brush, the locomotive spark, the lightning bolt, 
and, perhaps, at times, to the heating power of 
the sun's rays, concentrated by nodules of gum or 
resin, acting as burning-glasses. 

In the case of newly-settled countries, fires have 
been sometimes purposely started, for the purpose 
of readily obtaining an extended pasturage. 

The rapidity with which a forest fire spreads 
depends, of course, on the character of the trees 
and the force of the wind. It is also, however, 
dependent largely on the character of the soil. A 
rocky or sandy soil permits a fire to spread much 

e 6* 



66 OUTLINES OF FORESTRY. 

more rapidly than a damp soil. Some forests of 
soft and readily ignitible wood have a covering of 
moss on the soil, which permits the fire, when once 
started, to spread with awful rapidity. 

Extensive tracts in Sonth America, capable of 
sustaining dense forests, and originally covered by 
such, are now prevented from so doing by fires 
that are systematically started every year, for the 
purpose of obtaining a new growth of grass for 
pasturage. 

The power of the wind in causing the destruc- 
tion of the forest is, to a great extent, limited to 
the edges of the forest. In the midst of the forest, 
the trees stand so close together that they shield 
one another from the force of the wind. If, how- 
ever, an opening is made by the axe of the lumber- 
man, by fire, or by any other cause, the wind may 
cut a wide swath through the forest, and thus 
destroy many noble trees. 

"When rivers overflow their banks, thousands of 
acres of forest trees are often swept away, and in 
this manner considerable changes may occur in 
the general character of such districts. 

The timber thus thrown into the river channel 
often forms accumulations called rafts, which, be- 
coming fixed in certain parts of the stream, tend 



THE INANIMATE ENEMIES OF THE FOREST. 67 

to retard the free drainage of the country, and 
often result in marked changes in the river chan- 
nel. Such rafts are still found in the Mackenzie 
River, and formerly existed in parts of the Missis- 
sippi and the Red Rivers. 

The effects of the avalanche in sweeping away 
entire forests from the mountain slopes are well 
known. Like the influence of the wind, this effect 
is at first limited to the edges of the forest. If 
the forests are preserved, the further movement of 
the avalanche may be checked. In most moun- 
tainous countries, forests skirting villages are pre- 
served by rigorous penal laws. 

The protection from the destructive effects of 
avalanches afforded by forests on mountain slopes 
is shown in the following statement by filisee 
Reclus in a work entitled, " The Earth," * on page 
171: 

" The protecting woods of Switzerland and the Tyrol used to 
be defended by the national bann, and, as it were, ' tabooed/ 
They were, and still are, called the Bannwoelder. In the 
valley of the Andermatt, at the northern foot of the St. Goth- 

* Eeprinted, by permission, from " The Earth," by Elisee 
Eeclus. New York : Harper & Brothers, Publishers, Franklin 
Square. Pp. 573. 



68 OUTLINES OF FORESTRY. 

ard, the penalty of death was once adjudged on any man 
found guilty of having made an attempt on the life of one of 
the trees which shielded the habitations. Added to this, a 
sort of mystic curse was thought to hang over this impious 
action, and it was told with horror how drops of blood flowed 
when the smallest branch was broken off. It was true enough 
that the destruction of each tree might perhaps be expatiated 
by the death of a man." 

" The village and the great establishment of the baths at 
Bareges, in the Pyrenees, used to be menaced every year by 
avalanches rushing down from an elevation of four thousand 
feet, at an angle of thirty-five degrees. The inhabitants, 
therefore, were in the habit of leaving vacant spaces between 
the two quarters of the Bareges, so as to allow a free passage 
to the descending masses. Lately, however, they have en- 
deavored to do away with the avalanches by means somewhat 
similar to those employed by the Swiss mountaineers. They 
have thrown up banks from ten to twelve feet broad on the 
sides of the ravines, and have furnished these banks with an 
edging of cast-iron piles. Basket-work, and, here and there, 
walls of masonry, protect the young growing trees, which are 
gradually improving under the protection of these defensive 
works. In the mean time, until the real trees are strong 
enough to arrest the course of the snow, the artificial trees 
have well fulfilled the end they were destined for. In 1860, 
the year the defensive works were finished, the only avalanche 
which slid into the ravine did not exceed four hundred cubic 
yards in bulk ; while the masses which used to fall down upon 
the Bareges sometimes attained to more than ninety thousand 
yards in volume." 



THE INANIMATE ENEMIES OF THE FOREST. 69 

Lyell, in his " Principles of Geology," * on page 
440, speaks thus of the rafts in the Mississippi : 

" One of the most interesting features in the great rivers of 
this part of America is the frequent accumulation of what 
are termed 'rafts/ or masses of floating trees, which have 
been arrested in their progress by snags, islands, shoals, or 
other obstructions, and made to accumulate, so as to form 
natural bridges across the stream. One of the largest of these 
was called the raft of the Atchafalaya, an arm of the Missis- 
sippi, which branches off a short distance below its junction 
with the Eed Eiver. The Atchafalaya, being in a direct line 
with the general direction of the Mississippi, catches a large 
portion of the timber annually brought down from the north ; 
and the drift trees collected in about thirty-eight years previ- 
ous to 1816 formed a continuous raft, no less than ten miles in 
length, two hundred and twenty yards wide, and eight feet 
deep. The whole rose and fell with the water, yet was covered 
with green bushes and trees, and its surface enlivened in the 
autumn by a variety of beautiful flowers. It went on in- 
creasing till about 1835, when some of the trees upon it had 
grown to the height of about sixty feet. Steps were then taken 
by the State of Louisiana to clear away the whole raft and 
open the navigation, which was effected, not without great 
labor, in the space of four years." 

Dana, in his " Manual of Geology," f on page 

* " Principles of Geology," by Charles Lyell. London : 
Murray, 1872. Pp. 671. 
f Reprinted, by permission, from a "Manual of Geology," 



70 OUTLINES OF FORESTRY. 

657, gives the following description of the raft of 
the Red River : 

" The quantity of wood brought down by some American 
rivers is very great. The well-known natural ' raft' obstruct- 
ing the Red Eiver had a length, in 1854, of thirteen miles, and 
was increasing at the rate of one and a half to two miles a 
year, from the annual accessions. The lower end, which was 
then fifty-three miles above Shreveport, had been gradually 
moving up stream, from the decay of the logs, and formerly 
was at Natchitoches, if not still farther down the stream. 
Both this stream and the other carry great numbers of the 
logs to the delta." 

by James D. Dana. New York : Ivison, Blakeman, Taylor 
and Co., Publishers. Triibner & Co., London. Pp. 911. 



THE ANIMATE ENEMIES OF THE FOREST. 71 



VII. THE ANIMATE ENEMIES OF THE 
FOREST. 

The animate or living enemies of the forest 
are : 

1. Plants. 

2. Animals. 

3. Man. 

In classifying the enemies of the forest as ani- 
mate and inanimate, it should he borne in mind 
that the animate enemies of the forest often call 
to their aid the powers of inanimate nature. An 
example of this is seen in the case of the destruc- 
tion of forests by fire, which are more frequently 
started by man than in any other way. 

The influence of plants on the destruction of 
forests is limited mainly to the natural struggle 
which exists between the different forms of plant 
life for the possession of the soil. There are, 
however, many forms of parasitic plants, which, 
growing on the tallest and most vigorous trees, 
often in the end cause their destruction. 

A disease common in parts of Germany, called 



72 OUTLINES OF FORESTRY. 

the " schullkrankheit," often affects the pine for- 
ests. Trees attacked by this disease soon present 
the appearance of having been burnt over, their 
boughs and branches rapidly dying or drying up. 
The cause of the disease is not exactly known. It 
has, however, been ascribed to the presence of a 
fungous growth. 

In some parts of Iowa a fungous growth on the 
cottonwood trees has resulted in considerable dam- 
age to them. The fungus appears as an orange- 
yellow dust on the lower surfaces of the leaves. 

The animal enemies of the forest, like the winds, 
running water, or the avalanche, produce their 
most marked action on the borders or edges of the 
forest. 

In the deep recesses of the forest the vegetable 
kingdom holds almost undisputed sway. The life- 
giving power of the sun's light, and, to a great 
extent, that of its heat, are dissipated by the dense 
foliage that almost completely shuts out the light 
from the dank, gloomy ground. Animal life, to 
a great extent, is crowded out. Wherever the 
sunlight freely enters, animal life appears in 
myriad forms, until at length the forest again 
chokes it out of existence. 

The animal enemies of the forest are too numer- 



THE ANIMATE ENEMIES OF THE FOREST. 73 

ous to be more than merely mentioned. The 
following are among some of the more important : 

Domestic animals, which, when allowed to range 
freely through the woods, often cause much 
damage by gnawing at the bark of trees, or, in 
some cases, by the destruction of the foliage. 

Among wild animals, the rodents effect the 
greatest destruction by devouring the bark, and 
often completely girdling the trees. Among the 
worst of the rodents may be mentioned rabbits 
and mice, which gnaw the bark, or gophers, which 
eat the roots. Beavers, too, destroy forests, not 
only by the actual cutting down of the trees, but 
especially by building dams, and thus, by causing 
the overflow of the intervale, destroying all its 
growing timber. 

Goats and other animals live largely on the 
bark of trees. In certain parts of the earth, such, 
for example, as Assyria, Greece, Italy, Spain, and 
Morocco, the extensive forests which once covered 
them have been completely destroyed by the 
ravages of goats. 

In general, insects damage trees by feeding on 
the parts necessary for growth and reproduc- 
tion. Some insects damage trees by boring the 
trunks and branches in order to deposit their 



74 OUTLINES OF FORESTRY. 

eggs. In all cases the increase in the destruction 
produced by insect life can be traced to the indis- 
criminate and foolish slaughter of the insectivorous 
birds that formerly held such life in check. 

Caterpillars often cause considerable destruction 
to forest trees. 

The caterpillar of the pine bombyx often causes 
great ravages in the pine forests. In Germany 
these caterpillars are called pine-spinners, from the 
great number of cocoons with which they cover 
the pine-trees. Such caterpillars have been known 
to completely destroy extensive pine forests. The 
foresters are often compelled to set fire to portions 
of the forests in order to prevent the too rapid 
multiplication of this pest. 

Another caterpillar, which from its black and 
white coating is sometimes called the monk or 
nun caterpillar, is equally destructive, not only to 
forest trees like the pine, but also the other forest 
trees, such as the beech, oak, and birch. 

Other caterpillars cause great destruction to the 
forest by eating the tender buds or the young 
shoots. 

Grasshoppers often cause considerable damage 
to young trees by devouring the leaves, herbs, and 
tender shoots. 



THE ANIMATE ENEMIES OF THE FOREST. 75 

The larvae of insects do great damage to trees 
by boring chambers, or tunnellings, either in 
the heart-wood or in the layers of new wood 
which lie directly under the bark. The destruc- 
tive powers of such larvae are the more marked, 
since they work silently and in the dark, and their 
presence can scarcely be detected until they have 
caused the death of the tree. 

A beetle known as the typographer (Bostrychus 
typographies), from the shape of the galleries it 
burrows out in the trees, causes much damage to 
the forests, especially to the spruce-firs. Unfortu- 
nately, these insects breed very rapidly, and while 
in the larva state are capable of withstanding the 
most severe frosts. 

Some species of willows are severely injured by 
the larvae of a species of saw-fly, which strip the 
leaves and injure the tree generally. 

Perhaps the best remedy for the ravages of 
insects in general is to be found in the preserva- 
tion of insectivorous birds. 

The most powerful enemy of the forest, how- 
ever, is civilized man. The products of the forest 
are clearly man's right by gift of nature. He is 
lord of the forest as of the rest of the earth, and 
is, therefore, entitled to the use of the wood thus 



76 OUTLINES OF FORESTRY. 

grown for him. It is, however, by the abuse and 
not by the use of nature's lavish gifts that man 
deranges its economy, and thus brings on himself 
so much punishment. If he would only be careful 
to select trees of vigorous growth, and in cutting 
them down would exercise care that the remaining 
trees might live; if he would carefully preserve 
the soil, and hold in check the other enemies of 
the forest ; if he would wisely set aside large por- 
tions of the mountain slopes, the natural home of 
the forest, as areas on which trees should be con- 
tinually preserved, the earth would yield of her 
abundance all the wood required for his use. 

Referring to the insect enemies of the forest, 
Hough, in a report to the United States Commis- 
sioners of Agriculture,* page 263, in citing a 
writing of Grandjean, Conservateur des Forets, 
says: 

" The timber-tree particularly suffering from this cause was 
the Abies excelsa (D.C.), or common European spruce-fir, and 
the species of insects that did the injury were the Bostrychus 
typographicus and the B. chalcographicus, of which the first 

* Eeprinted, by permission, from the " Eeport on Forestry," 
submitted to Congress by the Commissioner of Agriculture, 
by Franklin B. Hough. Washington : Government Printing- 
office, 1882. Pp.318. 



THE ANIMATE ENEMIES OF THE FOREST. 77 

attacked the trunk and large branches, and the latter, which 
was seldom absent, found a lodgment in the smaller branches. 
Their habits were described as follows : 

" When the female of the typographic species is ready to de- 
posit her eggs, which occurs about the middle or latter part of 
spring, sooner or later, according to the temperature, she pene- 
trates the bark, and bores, almost invariably from below up- 
wards, a gallery that is cut along the outer layer of the sap- 
wood, depositing her eggs, as she advances, on the right side 
and the left. These are so quickly developed that the first 
larvae will have themselves made considerable galleries before 
the parent has finished. Each of these larvse digs a separate 
path of its own, more or less inclined to that made by the 
mother, and at the end of two or two and a half months they 
are transformed to a perfect insect, which in turn proceeds to 
lay a new lot of eggs, and, if favored by the heat of August, 
these are sometimes found more destructive than the first. 
This second growth is matured towards the end of September 
or beginning of October, and will be ready to resume opera- 
tions in the following spring. In the mean time they pass the 
winter under the mosses and in the crevices of the bark, where 
they endure the severest frosts of winter, for the perfect insect 
is as hardy as its larvse are tender. 

" The number of eggs deposited by one insect varies from 
twenty to one hundred and twenty or one hundred and thirty, 
and from this bark we may make some very instructive estimates. 
Suppose that each laying of sixty eggs produces specimens in 
which the sexes are equal, one female will have produced 
thirty others, which would each before the end of the year be 
represented by eighteen hundred of their kind. Half of these, 

7* 



78 OUTLINES OF FORESTRY. 

before the end of the second year, have produced eight hun- 
dred and ten thousand females, and by the end of the third 
year seven hundred and twenty-nine millions of the producing 
sex, and the forest will have fed one billion five hundred and 
six million six hundred thousand of the progeny of this one 
parent." 

Concerning the destructive effects of the animal 
kingdom, Geikie, in his " Text-Book of Geology,"* 
page 456, writes : 

"Many animals exercise a ruinously destructive influence 
on vegetation. Of the various insect plagues of this kind it 
will be enough to enumerate the locust, phylloxera, and Colo- 
rado beetle. The pasture in some parts of the south of Scot- 
land has, in recent years, been damaged by mice, which have 
increased in numbers owing to the indiscriminate shooting 
and trapping of owls, hawks, and other predaceous creatures. 
Grasshoppers cause the destruction of vegetation in some parts 
of Wyoming and other "Western Territories of the United 
States. The way in which animals destroy each other, often 
on a great scale, may likewise be included among the geologi- 
cal operations now under description." 

Speaking of the influence of certain insects in 
destroying forests from over extended districts, 

* Eeprinted, by permission, from a " Text-Book of Geology," 
by Archibald Geikie, LL.D. London : Macmillan & Co., 1882. 
Pp. 971. 



THE ANIMATE ENEMIES OF THE FOREST. 79 

Pouchet, in his work entitled the " The Universe, 
or the Infinitely Great and the Infinitely Little," * 
page 218, says : 

" If, when the warm breath of spring drives away the rigor 
of winter and renews life in the fields, we enter one of the 
great coniferous woods of Germany, we are astonished at the 
tumult and activity which prevail in lieu of the silence we 
went there to seek. Everything is in movement. 

" Groups of woodmen, foresters, and overseers move about by 
hundreds, and stretch away like columns of skirmishers ; it is 
a complete army in the field, which opens out wherever there 
is a large space, and of which the wings are sometimes lost in 
the windings of the roads, or hidden by the projection of some 
hillock. This mass of men always moves in order, distributed 
in troops commanded by experienced leaders. They are all 
provided with long weapons, which, at a distance, might be 
taken for lances. 

" Or, if the excursion is made by night, another spectacle 
awaits us. The whole forest seems on fire. In every part are 
burning great trees, erect and isolated, like huge threatening 
torches, the flame of which rises to the clouds and casts a 
baleful glance on all around. A few foresters, standing in 
silence, contemplate the progress of the conflagration, and 
watch its ravages. Lastly, at other times, as a final resource, 
the entire forest is given up a prey to the flames, and whirl- 

* Reprinted, by permission, from " The Universe, or the 
Infinitely Great and the Infinitely Little," by F. A. Pouchet, 
M.D. New York : Charles Scribner & Co., 1870. Pp. 790. 



80 OUTLINES OF FORESTRY. 

winds of fire, menacing and dreadful, spread on every side ; a 
woody region, formerly so fertile, is entirely devoured by fire, 
and only an immense mountain of charcoal remains of all this 
mass of wealth. 

" We ask, against what formidable enemy such an army of 
men has been launched ? Who are they going to attack with 
their rods which they brandish on all sides ? What redoubta- 
ble aggressors are the others attempting to stay the march of, 
with the long trenches they are scooping out? Why these 
frightful fires in the middle of the night ? Why this general 
conflagration ?" 



THE DESTRUCTION OF THE FOREST. 81 



VIII. THE DESTRUCTION OF THE 
FOREST. 

The removal of the forests from any consider- 
able section of country, in the end, is invariably 
followed by some or all of the following results : 

1. An increase in the frequency with which the 
rivers in that section of country overflow or inun- 
date their banks. 

2. An increase in the frequency and severity of 
droughts, as witnessed by a marked decrease in the 
amount of water in the river channels, and by an 
increase in the frequency with which the springs, 
in such section of country, either show a marked 
decrease in their flow or dry up altogether. 

3. A rapid loss of the soil from such areas, re- 
sulting from the more rapid surface drainage of 
their surfaces. 

4. A marked disturbance in the lower courses 
of the rivers, rising in or flowing through such 
section of country, produced by the filling up of 
their channels by sand-bars or mud-flats. 

/ 



82 OUTLINES OF FORESTRY. 

5. A decrease in the healthfulness of the district 
that borders on the lower courses of such rivers, — 
that is, in those portions which lie in the lowlands 
near the rivers' mouths. 

6. An increase in the number and severity of 
hail-storms, both over the areas themselves or in 
the countries bordering thereon. 

When the forests are removed from any section 
of country, that part of the rainfall which for- 
merly entered the ground, either by gradually 
sinking into the porous soil, or by running along 
the branches and trunks of the trees, and so enter- 
ing and penetrating the more deeply-seated strata, 
now drains rapidly off the surface. Instead of 
reaching the river channel quietly and slowly 
through discharge from the reservoirs of springs, 
it now rapidly drains directly off the surface into 
the river channel. 

Instead of draining into the river channel con- 
tinuously for a period of, say, three weeks, the 
rain-water now drains into the channel in often a 
period of as many hours. The channel rapidly 
fills, the river overflows its banks, and the floods so 
caused carry loss to the lowlands along the river 
banks, and, not infrequently, death to the inhabi- 
tants. 



THE DESTRUCTION OF THE FOREST. 83 

Not only are the riches of the rainfall thus 
squandered, to the loss of the inhabitants of the 
river valleys, from the excess of water immediately 
after a rainfall, but a still greater and more far 
reaching loss occurs from the failure of the rain- 
fall to fill the reservoirs of the springs, the contin- 
uous discharge of which are necessary to maintain 
the proper flow of water in the river. 

The springs, having their reservoirs but partly 
filled, are apt to fail shortly after the rainfall 
ceases, so that even limited droughts may cause 
them to dry up completely. 

The damage, however, does not stop here. The 
soil in which the forest grew, being no longer held 
together either by the roots of the trees or under- 
brush of the forest, or protected by a vegetable 
covering, is rapidly carried away by the water. 
The soil thus lost, resulted from the gradual dis- 
integration of hard rocks, and contains as essen- 
tial elements substances derived from the continued 
growth of former generations of plants, and prob- 
ably required centuries for its production. Its 
removal in a few years is, therefore, a serious 
matter. 

The soil, the wealth of the highlands, is now 
thrown into the river channel, and though some 



84 OUTLINES OF FORESTRY. 

of it fertilizes the lowlands, over which it is spread 
during inundations, yet much collects in sand-bars 
and mud-flats on the lower courses of the river. 
These flats work injury because : 

1. They hinder navigation, and thus interfere 
with the commerce between different parts of the 
country. 

2. They become sources of contamination to the 
air of the lowlands, by breeding miasmatic and 
other diseases. 

Besides the disturbances thus caused to the 
drainage of the region from which the forest has 
been removed, considerable changes are brought 
about in the rate at which the now bare soil re- 
ceives the heat from the sun, and the rapidity with 
which it throws it off into the air. 

Areas covered with forests both receive and part 
with their heat slowly, and are, therefore, not very 
apt to become very hot in summer, or very cold 
in winter. 

Bare areas, or areas stripped of their vegetable 
covering, both receive and part with their heat 
rapidly, and are, therefore, apt to become very hot 
in summer and very cold in winter. 

The presence of the forest, therefore, tends to 
prevent marked changes in the temperature of the 



THE DESTRUCTION OF THE FOREST. 85 

air, while the removal of the forest tends to permit 
sudden changes in such temperature. 

These effects will be considered under the gen- 
eral head of climate. 

The axe of the pioneer, so often regarded as the 
emblem of civilization, is more correctly to be 
regarded as an emblem of an entirely different 
character. 

The problem of the preservation and protection 
of the forest is one of extreme difficulty, for the 
following reasons : 

The dense populations which now exist in most 
of the temperate regions of the earth could not 
continue to exist in the forest regions which once 
grew on large parts of their areas. 

The regions best fitted for the growth of men 
are also best fitted for the growth of trees. Since 
civilized man cannot continue as a dweller in the 
forest, as the density of population increases, the 
forest must be cut down. 

In removing the forest to make way for man, 
certain areas should be set aside in all sections 
for the purpose of perpetually maintaining trees 
thereon. The nature of such areas will, of course, 
depend on a variety of circumstances. In general, 
however, it can be shown that, on the slopes of 

8 



86 OUTLINES OF FORESTRY. 

mountain ranges, which form the natural places 
where rivers rise, forests should be especially 
maintained. 

Laws should, therefore, be enacted providing for 
the replanting of trees on mountain slopes, either 
when they have been removed by the axe of the 
woodman, or by fire, or by any of the other 
enemies of the forest. 

The influence of the destruction of the forest 
on the rapidity of drainage, and the consequent 
liability to the destructive floods, is thus referred 
to by the author in his " Elements of Physical 
Geography," * page 64, as follows : 

" Influence of the Destruction of the Forests on Inundations. — 
When the forests are removed from a large portion of a river- 
basin, the rains are no longer absorbed quietly by the ground, 
but drain rapidly off its surface into the river channels, and 
thus in a short time the entire precipitation is poured into the 
main channel, causing an overflow. It is from this cause that 
the disastrous effects of otherwise harmless storms are pro- 
duced. The inundations are most intensified by this cause in 
the early spring, when the ice and snow begin to melt. The 
destructive effects of the floods are increased by the masses of 

* Eeprinted, by permission, from " The Elements of Physi- 
cal 'Geography," by Edwin J. Houston, A.M. Philadelphia : 
Eldredge & Brother, No. 17 North Seventh Street, 1891. Pp. 
172. 



THE DESTRUCTION OF THE FOREST. 87 

floating ice, which, becoming gorged in shallow places in the 
stream, back up the waters above. The increased frequency 
of inundations in the United States is, to a great extent, to be 
attributed to the rapid destruction of the forests." 

Sir Charles Lyell, in his "Principles of Ge- 
ology," * speaking of the effects produced by the 
removal of the forest, says, on page 457 : 

" When St. Helena was discovered, about the year 1506, it 
was entirely covered with forests, the trees drooping over the 
tremendous precipices that overhang the sea. Now, says Dr. 
Hooker, all is changed ; fully five-sixths of the island is en- 
tirely barren, and by far the greater part of the vegetation 
that exists, whether herbs, shrubs, or trees, consists of intro- 
duced European, American, African, and Australian plants, 
which propagated themselves with such rapidity that the na- 
tive plants could not compete with them. These exotic species, 
together with the goats, which, being carried to the island, de- 
stroyed the forests by devouring all the young plants, are sup- 
posed to have utterly annihilated about one hundred peculiar 
and indigenous species, all record of which is lost to science, 
except those of which specimens were collected by the late 
Dr. Burchell, and are now in the herbarium of Kew." 

The protective action o£ plants generally as pre- 
venting erosion by water or wind is clearly pointed 

* " Principles of Geology," by Sir Charles Lyell, M.A. 
London : John Murray, 1872. Pp. 652. 



88 OUTLINES OF FORESTRY. 

out by Geikie, in his " Text-Book of Geology," * 
on page 456. 

" The protective influence of vegetation is well known. 

" 1. The formation of a stratum of turf protects soil and rocks 
from being rapidly removed by rain or wind. Hence, the 
surface of a district so protected is denuded with extreme 
slowness except along the lines of its water-courses. 

" 2. Many plants, even without forming a layer of turf, serve 
by their roots or branches to protect the loose sand or soil on 
which they grow from being removed by wind. The common 
sand-carex and other arenaceous plants bind littoral sand- 
dunes and give them a permanence which would at once be 
destroyed were the sand laid bare again to storms. In North 
America the sandy tracts of the Western Territories are in 
many places protected by the sage-brush and grease-wood. 
The growth of shrubs and brushwood along the course of a 
stream not only keeps the alluvial banks from being so easily 
undermined and removed as would otherwise be the case, but 
serves to arrest the sediment in floods, filtering the water and 
thereby adding to the height of the flood-plain. On some parts 
of the west coast of France extensive ranges of sand-hills have 
been gradually planted with pine woods, which, while prevent- 
ing the destructive inland march of the sand, also yield a large 
revenue in timber, and have so influenced the climate as to 
make these districts a resort for pulmonary invalids. In tropi- 

* Keprinted, by permission, from a " Text-Book of Geology," 
by Archibald Geikie, LL.D. London : Macmillan & Co., 1882. 
Pp. 971. 



THE DESTRUCTION OF THE FOREST 89 

cal countries the mangrove grows along the sea-margin, and 
not only protects the land, but adds to its breadth, by forming 
and increasing a maritime alluvial belt." 

The following, from the " Journal of the Society 
of Arts," * shows the enormous demands made on 
the forest by railroads for sleepers : 

" The Belgian ' Bulletin du Musee Commercial' gives the 
following information respecting the number of sleepers used 
on various railways. In France alone the six larger railway 
companies require a daily supply of more than ten thousand 
sleepers, making an annual consumption of over three million 
six hundred and fifty thousand. As a tree of ordinary di- 
mensions cannot furnish more than ten logs, it follows that 
more than a thousand fine trees are cut down every day solely 
for the purpose of supplying the necessary sleepers for the 
French railways. In the United States the amount required 
is still greater. Over fifteen million sleepers are annually 
used in this country, thus necessitating the annual destruction 
of eighty thousand hectares, or one hundred and ninety-seven 
thousand six hundred acres of forests. 'The Bulletin du 
Musee Commercial' estimates at more than forty millions the 
number of logs required for the railways of the world, and is 
of opinion that the estimate is rather below than above the 
mark." 

* " Journal of the Society of Arts," vol. xxvii. London : 
George Bell & Sons, 6 York Street, Covent Garden, 1889. 
Pp. 924. 

8* 



90 OUTLINES OF FORESTRY. 



IX. THE EARTH'S OCEAN OF VAPOR. 

From every water surface on the earth there is 
almost constantly rising and passing into the air 
an invisible form of water called vapor. 

Vapor is formed wherever water is sufficiently 
heated under such circumstances that its particles 
have freedom to expand, and thus occupy a greater 
space. 

The waters of the earth are caused to pass into 
the atmosphere as vapor mainly by the heat of the 
sun. 

The vapor that passes into the air from the 
ocean and other water surfaces spreads or diffuses 
through the air, and is carried by the winds to 
different parts of the earth's surface. The air di- 
rectly over a water surface is, however, generally 
moister than that over a land surface. 

"When, by any cause, water vapor loses the heat 
which caused it to become a vapor, it again be- 
comes visible as dew, fog, cloud, or mist, or falls 
as rain, hail, or snow. 

The rapidity with which water surfaces throw 



THE EARTH'S OCEAN OF VAPOR. 91 

off vapor into the air varies with, the following 
circumstances : 

1. "With the amount of surface exposed. 
Evaporation takes place only at the surface; 

consequently, the greater the surface, the greater 
the rapidity of evaporation. When wet clothes 
are hung out to dry, they are so opened or spread 
out that the air can act on them from all sides. 
A pound of water placed in an open shallow dish, 
and exposed to the air, will evaporate much more 
rapidly than the same quantity would if placed in 
an open, narrow-necked bottle. 

For the same reason, an equal quantity of water 
will evaporate still more rapidly when sprinkled on 
the surface of a sheet hung out in the air to dry. 

2. On the temperature of the air. 

The capacity of a given volume of air for 
water in a state of vapor rapidly increases with 
its temperature. A cubic foot of dry air at the 
temperature of melting ice, or 32 degrees Fahren- 
heit, when saturated, holds a little more than half 
a grain of vapor. It then being saturated can 
hold no more water in an invisible state. In- 
crease its temperature, however, to 212 degrees 
Fahrenheit, and it can hold twenty grains, or 
about forty times as much as it formerly held. 



92 OUTLINES OF FORESTRY. 

Consequently, any increase in the temperature 
of air permits it to hold a greater quantity of 
vapor. Conversely, any decrease in the tempera- 
ture of air causes its ability to hold moisture as 
vapor to decrease. 

If, therefore, the temperature of the air be suffi- 
ciently decreased, a part of the vapor it contains 
will appear in some visible form. 

3. On the quantity of vapor already in the air. 
When a given bulk of air has as much vapor in 

it as it can hold, all evaporation ceases. Conse- 
quently, the drier the air over a water surface, the 
greater is the rapidity of evaporation. 

4. On the velocity of the wind. 

The wind brings fresh and drier air to the 
water surfaces, and at the same time removes the 
air into which such surfaces were discharging 
their vapor. An increase in the velocity of the 
wind, therefore, increases the rapidity of evapora- 
tion. 

5. On the pressure of the air. 

The greater pressure the air exerts on a water 
surface, the slower the rapidity of evaporation. A 
low barometer permits a water surface to throw off 
its vapor with much greater rapidity than a high 
barometer. 



THE EARTHS OCEAN OF VAPOR. 93 

"When clouds reach the higher regions of the 
atmosphere they disappear, because the particles 
of water of which they are composed pass rapidly 
into an invisible vapor, on account of the great 
relief of pressure in the higher regions. 

The earth's ocean of vapor is of the greatest 
importance to its present race of animals and 
plants. If any considerable change in either the 
quantity or distribution of vapor should be main- 
tained for any considerable time, the present race 
of animals and plants would disappear. 

Some of the more important ways in which the 
ocean of vapor affects the economy of the earth 
are as follows : 

1. By the action of the winds, the water vapor 
is carried from the warm regions of the earth to 
the colder regions, where, falling as rain or snow, 
it gives out its heat and raises the temperature of 
the air over such regions. 

An interchange is thus effected between the too 
great heat of the equatorial regions and the too 
feeble heat of the poles, and a more equable, uni- 
form temperature is insured than would otherwise 
exist. 

The earth's ocean of vapor therefore acts to 
moderate the excessive temperatures that would 



94 OUTLINES OF FORESTRY. 

otherwise exist both in the equatorial and in the 
polar regions. 

2. By acting as a screen interposed between the 
earth and the sun, and thus preventing the earth's 
surface from becoming too rapidly heated when 
exposed to the sun's rays, or too rapidly cooled 
when deprived of such rays. 

"Water enters so largely into the composition of 
both animals and plants, that its absence from any 
section of country invariably causes such section 
to become a desert. 

Within certain limits, the wealth of any section 
of country can be accurately estimated by the 
number of inches of rain that fall in a given time 
on its surface. This liquid wealth may be regarded 
as a species of bank account of such section of 
country, by which its solvency or bankruptcy may 
be determined. 

The ocean of vapor which forms the source from 
which the rains are derived is, therefore, of great 
importance to the operations of nature. 

Even a hurried glance at the map of the world 
will show that the earth's greatest expanse of water 
surface occurs near the equatorial regions. Here, 
also, the sun's heat is greatest. The air over the 
equatorial regions would become too enormously 



THE EARTH'S OCEAN OF VAPOR. 95 

heated to sustain the present life of the earth, were 
the water surfaces replaced by land. 

Not only does a water surface heat more rapidly 
than a land surface, but the vapor which arises 
from it, locks up much of the heat in a form that 
is sometimes popularly called latent heat. 

To change a pound of ice, at thirty-two degrees 
Fahrenheit, into a pound of water, at thirty-two 
degrees Fahrenheit, requires one hundred and 
forty-two heat units, or one hundred and forty- 
two times as much heat as is required to raise 
the temperature of a pound of water one degree 
Fahrenheit. To convert one pound of water at 
sixty degrees Fahrenheit into vapor requires nearly 
one thousand heat units, an amount of heat that 
would be able to raise more than six pounds of 
ice-cold water to the temperature of its boiling- 
point. When the vapor is condensed and falls as 
rain or snow, this heat reappears and raises the 
temperature of the air. "When, therefore, the ex- 
cessive heat of the sun in the equatorial regions 
falls on the extended water surfaces, much of the 
heat is absorbed by the vapor, and the air is pre- 
vented from growing too hot. This vapor is car- 
ried by the winds to the polar regions, where it 
gives up its heat to the air, and falls as rain or snow. 



96 OUTLINES OF FORESTRY. 

The vapor of water exerts another and still 
more powerful influence on the climate of the 
earth. "Water vapor possesses in a marked de- 
gree the power of absorbing heat rays of the sun. 
About twenty-eight per cent, of the heat of the 
vertical rays is absorbed before such rays reach 
the surface, provided there is a sufficient quantity 
of vapor in the air. When the heated earth throws 
off or radiates its heat into the atmosphere, the 
same water vapor absorbs a greater part of such 
rays, and rapid cooling by radiation is thus pre- 
vented. The presence of the water vapor, there- 
fore, prevents either the rapid heating of the 
earth's surface by the direct action of the sun's 
rays, or the rapid cooling of such surface by 
radiation. 

If the earth's surface were deprived of this 
screen of vapor, the air would become so rapidly 
heated on the rising of the sun, and so rapidly 
cooled on its setting, that the earth would be 
unable to sustain its present plant and animal 
life. 

Tyndall, speaking of the influence that the 
earth's water vapor exerts on the climate of Eng- 
land, says, " The removal for a single summer 
night of the clouds of vapor which cover Eng- 



THE EARTH'S OCEAN OF VAPOR. 97 

land would be attended by the destruction of 
every plant which a freezing temperature could 
kill." 

The amount of vapor in the air of any country, 
though dependent on the direction from which the 
winds come, is also markedly influenced by the 
nature of its surface. 

The presence of forests over any section of 
country has the effect of decreasing the rapidity 
with which the wet surface parts with or loses its 
water by evaporation. This decrease in the rapid- 
ity of evaporation is caused : 

(a.) Because the air over the forest is generally 
moister than that over the open fields, and evapo- 
ration takes place less rapidly in moist air. 

(b.) Because the ground in the forest is shielded 
from the direct rays of the sun. 

(c.) Because the wet ground is protected from 
the direct action of the wind. 

The presence of the forest, therefore, tends to 
keep the air moist for a longer time, and to thus 
prevent the occurrence of marked contrasts in the 
humidity of the air. 

Some experiments made in France show that 
the rapidity of evaporation is sixty-three per cent. 
less in the forest than in the open fields. 
e g 9 



98 OUTLINES OF FORESTRY. 

The influence of the vapor screen that is placed 
between any surface and the sun on the climate of 
the surface is thus referred to by Tyndall in his 
" Heat as a Mode of Motion," * on page 417 : 

" A few years ago a work possessing great charms of style 
and ingenuity of reasoning was written to prove that the more 
distant planets of our system were uninhabitable. Applying 
the law of inverse squares to their distances from the sun, the 
diminution of temperature was found to be so great as to pre- 
clude the possibility of human life in the more remote mem- 
bers of the solar system. But in those calculations the influ- 
ence of an atmospheric envelope was overlooked, and this 
omission vitiated the entire argument. An atmosphere may 
act the part of a barb to the solar rays, permitting them to 
reach the earth, but preventing their escape. A layer of air 
two inches in thickness, saturated with the vapor of sulphuric 
ether, would offer very little resistance to the passage of the 
solar rays, but I find that it would cut off fully thirty-five per 
cent, of the planetary radiation. It would require no inor- 
dinate thickening of the layer of vapor to double this ab- 
sorption ; and it is perfectly evident that, with a protecting 
envelope of this kind, permitting the heat to enter, but 
preventing its escape, a comfortable temperature might be 
obtained on the surface of the most distant planet." 

* Reprinted, by permission, from " Heat as a Mode of Mo- 
tion," by John Tyndall, LL.D., F.R.S. New York : Appleton 
and Company, 1883. Pp. 591. 



THE EARTHS OCEAN OF VAPOR. 99 

Alexander von Humboldt, in his " Cosmos," * 
thus refers to the vapor of the atmosphere, on 
page 330, of vol. i. : 

" As the quantity of moisture in the atmosphere increases 
with the temperature, this element, so important to the whole 
organic creation, varies with the hour of the day, the season 
of the year, and the degree of latitude and of elevation. Our 
knowledge of the hygrometric relations of the atmosphere has 
been materially augmented of late years by the method now 
so generally and extensively employed of determining the 
relative quantity of vapor, or the conditions of moisture of 
the atmosphere, by means of the difference of the dew point 
and of the temperature of the air, according to the ideas of 
Daniell and of Dalton, and by the use of the wet-bulb ther- 
mometer. Temperature, atmospheric pressure, and the di- 
rection of the wind have all a most intimate relation to the 
atmospheric moisture so essential to organic life. The influ- 
ence, however, of humidity on organic life is less a con- 
sequence of the quantity of vapor held in solution under 
different zones than the nature and frequency of the aqueous 
precipitations which refresh the ground in the form of dew, 
mist, rain, or snow." 

* " Cosmos," vol. i., by Alexander von Humboldt. Lon- 
don : Longman, Brown, Green & Longmans, 1849. Pp. 487. 



100 OUTLINES OF FORESTRY. 



X. RAIN. 

The vapor which rises from the surface of the 
ocean, and, indeed, from all water surfaces, mixes 
or diffuses through the air, and is carried by the 
winds to different parts of the earth. The air over 
parts of the earth at considerable distances from 
any large body of water may therefore contain 
much vapor. 

The quantity of water the air can hold, in an 
invisible state as vapor, increases rapidly with an 
increase in the temperature. Consequently, when 
air containing vapor is considerably chilled, it can 
no longer hold as much as it formerly did, and a 
part appears as rain, or as some other form of pre- 
cipitation, such as dew, snow, hail, fog, cloud, etc. 

The amount of water that falls, or is precipitated 
from the air, depends not only on the quantity of 
air that is chilled, and on the extent of this chill- 
ing, but also on the quantity of moisture the air 
contained before it was chilled. 

The lowering of temperature necessary to pro- 
duce rain may be caused in the following ways : 



RAIN. 101 

1. The moist air may blow along the earth's 
surface towards colder regions. 

2. The moist air may rise directly from the 
earth's surface into the higher and colder regions 
of the air. 

As a rule, the moist air which blows along the 
earth's surface towards the poles becomes chilled 
and deposits its moisture as rain or snow. On the 
contrary, the moist air which blows along the 
earth's surface towards the equator becomes, for 
the greater part, warmer and, thus, becoming 
drier takes rather than gives moisture, and pro- 
duces drought. 

Therefore, as a rule, only the surface winds 
which blow towards the colder regions of the 
earth can be expected to bring rain. 

In the tropical regions, however, any wind, 
whether from the equator or from the poles, which 
has crossed the ocean or any other large body of 
water, and has thereby become saturated with 
moisture, will deposit some of its moisture as rain 
when it strikes the cooler coasts of a continent or 
island. Even in such cases, however, the equa- 
torial winds are more apt to cause heavy rainfalls 
than those from the poles. 

A warm, moist air, when sufficiently chilled, will 
9* 



102 OUTLINES OF FORESTRY. 

cause a heavier rainfall than a cold, moist air, be- 
cause the warm air has a greater capacity for hold- 
ing vapor. 

In general, the air of the equatorial zones of the 
earth is both warmer and moister than that of the 
temperate zones, and the air of the temperate zones 
is both warmer and moister than that of the polar 
zones. 

Consequently the rainfall is heaviest in the equa- 
torial zones, and is greater in the temperate zones 
than in the polar zones. 

The air near the coast of a continent or island is 
moister than that over the interior. Consequently 
the rainfall is heavier on the coasts than in the 
interior. 

When the earth's surface is intensely heated, the 
air over it becomes so hot that it rises far above the 
surface. If sufficiently moist, the chilling so caused 
produces a heavy rainfall. Much of the rain in 
the tropical regions is caused in this manner. 

Mountains form excellent means for cooling the 
air and causing its invisible water or vapor to fall 
as rain. They act no matter from what direction 
the wind may be blowing. 

"When the wind blows against the sides or slopes 
of a mountain, it is forced by the pressure of the 



RAIN. 103 

wind behind it to slowly creep up the slopes of the 
mountain, and becomes chilled in the colder re- 
gions which lie near the summit. If this lowering 
of temperature be sufficiently great, the moisture 
will be precipitated from the air, no matter from 
what direction the wind may come. 

Mountains may, therefore, cause rain to fall 
from any wind that is forced to blow over them, 
provided they are sufficiently high to cause the 
necessary amount of cooling. When a mountain 
reaches sufficiently far upward into the air to cause 
the temperature to fall below the freezing-point 
of water, the condensed moisture falls as snow. 

The reason so many rivers rise in mountains is 
to be found in the fact that the mountains act to 
chill the winds, and so rob the air of its moisture, 
no matter in from what direction the wind, which 
is forced to ascend their slopes, may happen to 
blow. 

Nearly all the rivers of the world rise in moun- 
tainous districts. As a rule, the largest rivers of 
the world rise in the highest mountains. This is 
because the higher the mountain the colder its 
slopes, the cold mountain slopes acting, as ex- 
plained, to deprive the air of its moisture. 

The rain that falls on a mountain's slopes, like 



104 OUTLINES OF FORESTRY. 

that which falls on any other part of the earth's 
surface, either runs rapidly off the surface or 
sinks slowly into the ground. 

The part that runs directly off the ground will 
be greater than the part which sinks into the 
ground, when the surface is bare and devoid of 
vegetation. On the contrary, the part which sinks 
into the ground will be greater than the part which 
runs directly oft' the surface, when the surface is 
covered by forests. But the proportion of the 
rainfall which sinks into the ground, as compared 
with that which runs directly off the surface, is 
greater where the sides of mountains are covered 
with forests than in any other case. 

Since the rivers which rise in the mountains are 
more regularly fed by the springs when the greater 
part of the rainfall sinks quietly into the ground, 
and since this occurs on mountains that are 
covered with trees, the importance of keeping the 
sides of the mountains well wooded is evident. 

When the sides of mountains are covered with 
forests, the rivers that rise on their slopes are not 
only less apt to overflow their banks during heavy 
rainfalls, but are also less apt to dry up and be- 
come shallow during droughts, than if such forests 
were removed. 



RAIN. 105 

The forests should, therefore, be preserved on the 
mountain-sides, in order to protect the lowlands 
either from inundations or floods, or from the 
effects of too small a quantity of water in the 
rivers which flow through them during droughts. 

The action of mountains in cooling the air and 
causing the condensation of the moisture of the 
air, is thus referred to by Tyndall in his " Heat as 
a Mode of Motion," * page 384 : 

" Mountains act as condensers, partly by the coldness of 
their own masses, which they owe to their elevation. Above 
them spreads no vapor screens of sufficient density to intercept 
their heat, which, consequently, passes unrequited into space. 
"When the sun is withdrawn, this loss is shown by the quick 
descent of the thermometer. The difference between a ther- 
mometer which, properly protected, gives the true tempera- 
ture of the night-air, and one which is permitted to radiate 
freely towards space, must be greater at high elevations than 
at low ones. This conclusion is confirmed by observation. 
On the Grand Plateau of Mont Blanc, for example, MM. 
Martins and Bravais found the difference between two such 
thermometers to be twenty-four degrees Fahrenheit, when 
a difference of only ten degrees was observed at Chamouni." 

* Eeprinted, by permission, from " Heat as a Mode of Mo- 
tion," by John Tyndall, LL.D., F.R.S. New York : D. Apple- 
ton & Co., 1883. Pp.591. 



106 OUTLINES OF FORESTRY. 

Huxley, in his " Physiography," * speaks as 
follows, concerning the formation of rain, on page 
47: 

" In examining the distribution of rain, it will be found to 
be regulated partly by the physical features of the country, 
and partly by the character of the prevailing winds. In the 
neighborhood of mountains, the rainfall is increased, since, as 
has already been pointed out, a mass of moist air, when forced 
up the side of a mountain, is chilled in the ascent, and its 
moisture consequently discharged. Among our western coun- 
ties, in the neighborhood of hills, the rainfall rises to eighty, 
or even to a hundred, inches, and upwards ; while away from 
hills, though still in the west, it is only from thirty to forty- 
five inches. A table-land, or high plain surrounded by moun- 
tains, will generally receive but little rain, since the winds 
which reach it have been more or less drained of moisture in 
sweeping over the surrounding hills. For a like reason, but 
little rain is likely to fall on the lee side of a high hill, and 
many mountains, consequently, have a wet and a dry side ; 
the wet side being, of course, that towards which the predomi- 
nant winds blow. As regards the influence of winds on rain, 
it is evident that, when air has blown over a large expanse of 
warm water, it must have become laden with moisture, which 
will be readily precipitated on exposure to refrigerating influ- 
ences. Hence, as in Britain, so in the greater part of Europe, 
the southerly and westerly winds bring rain ; and most rain 

* Reprinted, by permission, from " Physiography," by T. H. 
Huxley, F.R.S. London : Macmillan & Co., 1883. Pp. 384. 



RAIN. 107 

falls in the exposed westerly parts, such as the coast of Portu- 
gal, Spain, France, Britain, and Norway. There are certain 
conditions, however, under which rain is brought to our islands 
by easterly rather than westerly winds." 

Maury, in his " Physical Geography of the 
Sea," * on page 120, says : 

" We shall now be enabled to determine, if the views which 
I have been endeavoring to present be correct, what parts of 
the earth are subject to the greatest fall of rain. They should 
be on the slopes of those mountains which the trade-winds or 
monsoons first strike after having blown across the greatest 
tract of ocean. The more abrupt the elevation, and the shorter 
the distance between the mountain-top and the ocean, the 
greater the amount of precipitation. If, therefore, we com- 
mence at the parallel of about thirty degrees north in the Pa- 
cific, where the northeast trade-winds first strike that ocean, and 
trace them through their circuits till they meet high land, we 
ought to find such a place of heavy rains. Commencing at 
this parallel of thirty degrees, therefore, in the North Pacific, 
and tracing thence the course of the northeast trade-winds, 
we shall find that they blow thence, and reach the region of 
equatorial calms near the Caroline Islands. Here they rise 
up; but, instead of pursuing the same course in the upper 

* Eeprinted, by permission, from " The Physical Geography 
of the Sea, and its Meteorology," by M. F. Maury, LL.D., 
U.S.N. New York : Harper & Brothers, Publishers, Franklin 
Square. 



108 OUTLINES OF FORESTRY. 

stratum of winds through the southern hemisphere, they, in 
consequence of the rotation of the earth, are made to take a 
southeast course. They keep in this upper stratum until they 
reach the calms of Capricorn, between the parallels of thirty 
degrees and forty degrees, after which they become the pre- 
vailing northwest winds of the southern hemisphere, which 
correspond to the southwest of the northern. Continuing on to 
the southeast, they are now the surface winds ; they are going 
from warmer to cooler latitudes ; they become as the wet 
sponge, and are abruptly intercepted by the Andes of Pata- 
gonia, whose cold summit compresses them, and with its low 
dew-point squeezes the water out of them. Captain King found 
the astonishing fall of water here of nearly thirteen feet (one 
hundred and fifty-one inches) in forty-one days ; and Mr. Dar- 
win reports that the sea -water along this part of the South 
American coast is sometimes quite fresh, from the vast quan- 
tity of rain that falls. A similar rainfall occurs on the sides 
of Cherraponjie, a mountain in India. Colonel Sykes reports 
a fall here during the southwest monsoons of six hundred and 
five and one-quarter inches. This is at the rate of eighty-six 
feet during the year ; but King's Patagonia rainfall is at the 
rate of one hundred and fourteen feet during the year. Cher- 
raponjie is not so near the coast as the Patagonia range, and 
the monsoons lose moisture before they reach it." 



DRAINAGE. 109 



XI. DRAINAGE. 

The rain that falls on the earth either runs 
directly off the surface or sinks into the ground. 

The part that runs directly off the surface col- 
lects in small streams that discharge through a 
river, either into a lake or into the ocean. 

The part which sinks into the ground collects in 
pockets or places below the surface, called reser- 
voirs. As a rule, the water escapes from these 
underground reservoirs by coming out at the sur- 
face at some lower level, as a spring. During most 
of the time the flow of water in a river is kept 
up by the springs pouring their waters into the 
many streams that empty into the river channel. 

The water, therefore, that falls from the sky as 
rain, flows directly from the earth's surface into a 
river, or first collects in a reservoir, from which it 
afterwards flows into a river. 

The running of the water from the level where 
the rain fell to a lower level is called drainage. 

There are two kinds of drainage : 
10 



110 OUTLINES OF FORESTRY. 

1. Surface drainage, or where the rain-water 
runs directly off the surface. 

2. Underground drainage, or where the rain- 
water first sinks into the ground and then dis- 
charges as springs into some stream that empties 
into a river. 

Surface drainage, for the greater part, takes 
place rapidly, and occurs mainly during the time 
rain is falling. It practically stops a few hours 
after the rain ceases. 

Underground drainage takes place slowly, and 
may continue for many weeks after the rain ceases. 

All the water in a river comes from the rain that 
falls on the earth's surface. The rivers continue 
to flow hecause the springs are continually empty- 
ing their waters into the rivers, and, before they 
run dry, more rain falls and keeps up the supply 
in their reservoirs. 

Some rivers are larger than others. This is 
because : 

1. More rain falls on those parts of the earth 
through which they flow. 

2. The land which slopes towards such rivers 
covers a greater part of the earth's surface. 

The water runs off the earth from a higher to a 
lower level, because water runs down hill. The 



DRAINAGE. Ill 

direction in which water will drain from the land 
will depend on the direction of the slope of the 
land. If a large area of land so slopes that all the 
water draining from it collects in streams flowing 
into the ocean through a common river mouth, 
and the rainfall on such area is large, the river 
itself will be large. 

The smaller streams and rivers which collect in a 
single and larger river, and discharge their waters 
through a common mouth, are called, collectively, 
a river system. 

The area of land that drains into a river is called 
a river basin. 

The size of a river, therefore, depends upon the 
amount of the rainfall on its basin, and on the size 
of its basin. 

"When the quantity of water discharged into a 
river is greater than its channel can hold, a flood 
occurs, or the river is said to inundate its banks. 

A heavy rain-fall does not necessarily produce 
an inundation. If the character of the river basin 
is such that a comparatively small part of the rain- 
fall runs directly off the surface, and a large part 
sinks into the ground and collects in the reservoirs 
of springs, and slowly passes through such springs 
into the rivers, sufficient time may be given for 



112 OUTLINES OF FORESTRY. 

the river to safely discharge the waters of even a 
very heavy rainfall. 

If, however, the character of the surface is such 
that the larger part of the rainfall runs directly off 
the slopes into the river channel, then an inunda- 
tion must necessarily attend every heavy rainfall. 

If the greater part of the rainfall runs directly 
off the surface into the river channel, and a com- 
paratively small part goes to feed the reservoirs of 
the springs, and if a long time elapses before the 
next rainfall, the springs will dry up, and the 
water in the river will get very low. 

Any disturbance in the natural drainage of a 
country may cause a damage of two different 
kinds: 

1. The damage due to the overflowing of the 
rivers, or that directly due to too much water. 

2. The damage due to the drying up, or the 
getting too low, of the rivers in the intervals be- 
tween the storms, or that due to too little water. 

The proportion of the rainfall that sinks quietly 
into the earth, as compared with that which flows 
directly off its surface, depends on the character 
of the surface. As a rule, a surface devoid of 
vegetable covering — that is, a surface on which 
no vegetation is growing — will permit a larger 



DRAINAGE. 113 

proportion of the rainfall to drain directly into the 
river channels than will a surface covered by 
vegetation. This is especially the case during the 
colder parts of the year, when the ground is frozen. 

When rain falls on a surface covered by vegeta- 
tion, the water, by slowly trickling down the stalks 
or stems of the leaves and the branches and trunks 
of the trees, finds a ready entrance into the ground 
by following their surfaces and discharging into 
the porous ground lying around their roots. 

A forest permits this action of the water in sink- 
ing into the ground to take place quite readily. 

A forest, therefore, tends to decrease the amount 
of rainfall that drains directly from the earth's 
surface. 

A forest also tends to prevent the occurrence of 
too little water in a river, because it insures the 
filling of the reservoirs of springs, which discharge 
their waters into the rivers during the intervals 
between the rainfalls. 

Unless, therefore, forests are preserved, the 
proper drainage of the earth will be disturbed, 
and the rivers will have too much water in their 
channels during the time of rains, and too little 
water in the intervals between rains. 

The rapid drainage of the surface when no 

h 10* 



114 OUTLINES OF FORESTRY 

longer protected by the forests is thus described 
by Sir Charles Lyeil, in his " Principles of Ge- 
ology, or the Modern Changes of the Earth and 
its Inhabitants," * on page 338, vol. i. : 

" When travelling in Georgia and Alabama in 1846, I saw 
in both these States the commencement of hundreds of val- 
leys in places where the native forests had recently been re- 
moved. One of these newly-formed gulleys or ravines is 
represented in the annexed wood-cut, from a drawing which 
I made on the spot. It occurs three miles and a half due west 
of Milledgeville, the capital of Georgia, and is situated on the 
farm of Pomona, on the direct road to Macon. 

" In 1826, before the land was cleared, it had no existence ; 
when the trees of the forest were cut down, cracks three feet 
deep were caused by the sun's heat in the clay ; and during 
the rains, a sudden rush of water through the principal crack 
deepened it at its lower extremity, from whence the excavating 
power worked backward, till, in the course of twenty years, a 
chasm measuring no less than fifty-five feet in depth, three 
hundred yards in length, and varying in width from twenty to 
one hundred and eighty feet, was the result. The high road 
had been several times turned to avoid this cavity, the enlarge- 
ment of which is still proceeding, and the old line of road may 
be seen to have held its course directly over what is now the 
widest part of the ravine. In the perpendicular walls of this 

* "Principles of Geology," by Sir Charles Lyell, F.R.S., 
M.A. London: John Murray, Albemarle Street, 1872. Pp. 
650. 



DRAINAGE. 115 

great chasm appear beds of clay and sand, red, white, yellow, 
and green, produced by the decomposition in situ of hornblen- 
dic gneiss with layers and veins of quartz, which remains en- 
tire to prove that the whole mass was once crystalline." 

Marsh, in his book on " The Earth as Modified 
by Human Action," * in referring to the effects 
produced on the drainage of the land by the de- 
struction of the forest, on page 254, gives the fol- 
lowing quotation from a paper read by Blanqui, 
read before the Academy of Moral and Political 
Science in 1843, concerning the Alps of Provence : 

" The Alps of Provence present a terrible aspect. In the 
more equable climate of Northern France, one can form no 
conception of those parched mountain gorges where not even 
a bush can be found to shelter a bird, where, at most, the wan- 
derer sees in summer here and there a withered lavender, 
where all the springs are dried up, and where a dead silence, 
hardly broken by even the hum of an insect, prevails. But if 
a storm bursts forth, masses of water suddenly shoot from the 
mountain heights into the shattered gulfs, waste without irri- 
gating, deluge without refreshing the soil they overflow in 
their swift descent, and leave it even more seared than it was 
from want of moisture. Man at last retires from the fearful 

* Reprinted, by permission, from " The Earth as Modified 
by Human Action," by George P. Marsh. New York : Scrib- 
ner, Armstrong & Co., No. 654 Broadway, 1874. Pp. 656. 



116 OUTLINES OF FORESTRY. 

desert, and I have, the present season, found not a living soul 
in districts where I remember to nave enjoyed hospitality 
thirty years ago." 

The influence of a vegetable covering on the 
drainage of the surface is thus referred to by fili- 
see Reclus, in his work on " The Earth : A De- 
scriptive History of the Phenomena of the Life of 
the Globe," * on page 223 : 

" The action of vegetation is not confined merely to imbibing 
the water falling from the clouds ; it often, also, assists the 
superabundant moisture in penetrating the interior of the 
ground. Trees, after they have received the water upon their 
foliage, let it trickle down drop by drop on the gradually 
softened earth, and thus facilitate the gentle permeation of 
the moisture into the substratum ; another part of the rain- 
water, running down the trunk and along the roots, at once 
finds its way to the lower strata. On mountain slopes, the mosses 
and the freshly-growing carpet of Alpine plants swell like 
sponges when they are watered with rain or melted snow, and 
retain the moisture in the interstices of their leaves and stalks 
until the vegetable mass is thoroughly saturated and the liquid 
surplus flows away. Peat-mosses especially absorb a very con- 
siderable quantity of water, and form great feeding-reservoirs 
for the springs which gush out at a lower level. The immense 

* Eeprinted, by permission, from " The Earth," by Elisee 
Reclus. New York: Harper & Brothers, Franklin Square. 
Pp. 573. 



DRAINAGE. 117 

fields of peat which cover hundreds and thousands of acres on 
the mountain slopes of Ireland and Scotland may, notwith- 
standing their elevation and inclined position, be considered 
as actual lacustrine basins containing millions of tons of water 
dispersed among their innumerable leaflets. The supera- 
bundant water of these tracks of peat-mosses issues forth in 
springs on the plains below." 

The protective action of a vegetable covering is 
thus alluded to by Prestwich in his " Geology, 
Chemical, Physical, and Stratigraphical," * page 
136: 

" This surface soil, with its usual covering of herbage, serves 
to protect the land from further degradation, and checks the 
denuding action which would otherwise scour the surface after 
every shower of rain. Instances have been adduced to show 
how persistent are the features of such a surface. The posi- 
tions of the many dolmens and other so-called ' Druidical' 
stones, so common on the downs of this country and in many 
parts of France, shows that the level of the vegetable soil has 
undergone little or no change since they were first erected. 
The camp of Attila, situated in the great chalk plains of 
Champagne, furnishes a well-known date, namely, A.D. 451. 
Notwithstanding its more than fourteen hundred years, the 

* Eeprinted, by permission, from " Geology, Chemical, Physi- 
cal, and Stratigraphical," by Joseph Prestwich, M.A., F.E.S. 
Vol. i. Oxford, Clarendon Press, 1886. Pp. 477. 



118 OUTLINES OF FORESTRY. 

surface of this great earthwork, which is merely covered with 
a thin growth of grass, remains almost as perfect and as sharp 
as when first made and grassed over. Nothing of importance 
has been removed from the surface by mechanical means, what- 
ever may have been the solvent action of the rain on the rocks 
beneath." 



CLIMATE. 119 



XII. CLIMATE. 

By the climate of a country is meant the condi- 
tion of its atmosphere as regards heat or cold, 
moisture or dryness, healthfulness or unhealthful- 
ness. 

The atmosphere, or ocean of air that surrounds 
the earth, gets practically all its heat from the 
sun, either directly hy absorption as the rays pass 
through the air, or indirectly from the heated 
earth. 

Or, less concisely, the atmosphere receives its 
heat from the sun : 

1. Directly, by absorption. 

2. Indirectly, from the heated earth. 
(a.) By contact with the heated earth. 

(b.) By radiation from the heated earth, — that is, 
the sun's rays heat the earth, and the heated earth 
throws out or radiates its heat in all directions. 

(c.) By reflection from the heated earth, — that is, 
the sun's rays strike the earth and fly off from it 
like light does when it strikes a mirror. 

The equatorial regions of the earth are warmer 



120 OUTLINES OF FORESTRY. 

than either the temperate or the polar regions, 
because they receive the sun's rays more directly 
than any other part of the earth. 

Regions of the earth that are situated the same 
distance from the equator, however, often possess 
different temperatures, not only because they are 
exposed to warmer or colder currents of air or 
water, but also on account of certain peculiarities 
of their surfaces 

The distribution of the land and water areas of 
the earth exerts a marked influence in causing a 
difference in climate in regions situated in the 
same latitude. 

A given quantity of the sun's heat falling on a 
given area of water will produce therein a smaller 
increase of temperature than if permitted to fall 
on an equal area of land. Consequently, the air 
over such body of water will be less warmed than 
would the air over the land. 

"Water possesses a greater capacity for heat than 
any other common substance; in other words, a 
greater quantity of heat is required to cause a cer- 
tain increase of temperature in a pound of water 
than in a pound of any other common substance. 

For example : the quantity of heat required to 
raise a pound of ice-cold water to its boiling-point, 



CLIMATE. 121 

or to 212 degrees Fahrenheit, would be sufficient 
to raise the temperature of a pound of ice-cold 
iron to about 1600 degrees Fahrenheit, or to make 
the ice-cold iron red-hot. 

Although land and water areas may be situated 
in the same latitude, and therefore receive equal 
quantities of the sun's heat per unit of area, yet 
the temperature of the land, and consequently of 
the air over it, would become much hotter than 
the temperature of the water, and of the air over 
the water. 

The higher the temperature of an area, the more 
rapidly it loses its heat. A land surface, when 
heating, becomes hotter than a water surface when 
similarly exposed for the same time to the sun's 
heat. The land also, when cooling, loses its heat 
more rapidly than the water ; the air over the land 
becomes chilled sooner than over the water. 

Differences in the elevation of the land produce 
differences in the climate. In general, an elevation 
of three hundred and fifty feet will cause as great 
a lowering of temperature as a difference of one 
degree of latitude, or of about seventy geograph- 
ical miles. Therefore, the same differences are 
observed in passing from the base to the summit 
of a high tropical mountain as are observed in 

V 11 



122 OUTLINES OF FORESTRY, 

passing along the surface of the earth from the 
equator to the poles. Or, in other words, three 
hundred and fifty feet skyward equals seventy 
miles poleward. 

In summer, when the sun is more nearly over- 
head, and when in our hemisphere the earth is 
gaining rather than losing heat, the land areas, 
and consequently the air over them, rapidly become 
heated; while the water areas, and consequently 
the air over them, remain comparatively cool. 

In winter, however, when the loss of heat is 
greater than the gain, the land areas, and conse- 
quently the air over them, rapidly become cooled; 
while the water areas continue for a long time to 
part with the great stores of heat that they have 
taken in during the summer, and thus remain 
comparatively warm. 

Similar differences are observed between the 
temperature of the air over the land and water 
areas during the daylight while they are exposed 
to the sun's heat, and during the night when they 
are throwing it off*. 

There is another reason why the water areas are 
heated less rapidly than the land areas : the heat 
penetrates the water to a comparatively great 
depth, is diffused through a great body of water, 



CLIMATE. 123 

and, consequently, heats it less. Moreover, the 
water when heated is set in motion by reason of 
the differences of density produced by the differ- 
ences of temperature, and moves towards colder 
districts, and its place is taken by water that moves 
from colder districts. Such motions are seen in 
the constant ocean currents. 

The land, on the contrary, is heated to a com- 
paratively small depth, remains in its place, and 
may, therefore, rapidly become intensely hot. 

The climate produced by an extended land area 
is called a continental climate. That produced by 
an extended water area is called an oceanic climate. 
The continental climate is characterized by great 
extremes of heat and cold, — that is, a continental 
climate is apt to be very hot in summer and very 
cold in winter. The oceanic climate, on the con- 
trary, is characterized by a comparatively uniform 
temperature, being neither very hot in summer nor 
very cold in winter. 

So far as the climate of the land is concerned, 
the differences of climate above referred to are 
greatly influenced by the nature of the surface. 
If the surface is covered by vegetation of any kind, 
especially by forests, it both heats slowly and cools 
slowly. 



124 OUTLINES OF FORESTRY. 

If entirely bare, or deprived of vegetable cover- 
ing, it both heats quickly and cools quickly. 

The climate of a forest, or, indeed, even of a re- 
gion protected by a less dense covering of vegeta- 
tion, closely resembles the equable climate of a 
water area; that of a bare, arid district, differs 
greatly from that of a water area. Deserts, for 
example, are characterized by great extremes of 
climate, being very warm in summer, or in the 
daytime, and very cold in winter, or at night. 

The climate of a country, therefore, will be 
greatly influenced by the presence of the forest 
districts, and must necessarily be changed, to a 
greater or less extent, by the removal of such 
forests from extended areas. 

Humboldt, in " Cosmos," * on page 318, thus 
describes the influence of land and water areas on 
oceanic or continental climates ; or, as he styles 
them, on the insular or littoral climates : 

"I have already alluded to the slowness with which the 
great mass of water in the ocean follows the variations of 
temperature in the atmosphere, and the consequent influence 
of the sea in equalizing temperatures ; it moderates both the 

* " Cosmos," vol. i., by Alexander von Humboldt. London : 
Longman, Brown, Green & Longmans, 1849. Pp. 480. 



CLIMATE. 125 

asperity of winter and the heat of summer : hence arises a 
second important contrast, — that between insular or littoral 
climates (enjoyed also in some degree by continents whose 
outline is broken by peninsulas and bays), and the climate of 
the interior of great masses of solid land. Leopold von Buch 
was the first writer who entered fully into the subject of this 
remarkable contrast, and the varied phenomena resulting from 
it ; its influence on agriculture and vegetation, on the transpar- 
ency of the atmosphere and the serenity of the sky, on the 
radiation from the surface, and on the height and limit of per- 
petual snow. In the interior of the Asiatic continent, Tobolsk, 
Barnaul on the Obi, and Irkutsk have summers which, in 
mean temperature, resemble those of Berlin and Munster, and 
that of Cherbourg in Normandy, and during this season the 
thermometer sometimes remains for weeks together at 30° and 
31° C. (86° or 87.8° F.) ; but these summers are followed by 
winters in which the coldest month has the severe mean tem- 
perature of 18° to 20° C. (—4° to +4° F.)." 

Flammarion, in his work entitled " The Atmos- 
phere," * referring to the contrasts between con- 
tinental and oceanic climates, says, on page 250 : 

" The climate of Ireland, Jersey and Guernsey, of the Pen- 
insula of Brittany, of the coasts of Normandy, and the South 
of England, countries in which the winters are mild and the 

* Eeprinted, by permission, from " The Atmosphere," by 
Camille Flammarion. New York : Harper & Brothers, Frank- 
lin Square, 1873. Pp. 454. 

11* 



126 OUTLINES OF FORESTRY. 

summers cool, contrast very strikingly with the continental 
climate of the interior or Eastern Europe. In the northeast 
of Ireland (54° 56 / ), in the same latitude as Konigsberg, the 
myrtle grows in the open ground just as it does in Portugal. 
The temperature of the month of August in Hungary is 69.8° ; 
in Dublin (upon the same isothermal line of 49°) it is 61° at 
most. The mean temperature of winter descends to 36.3° at 
Buda. In Dublin, where the annual temperature is only 49°, 
that of the winter is, nevertheless, 7.7° above the freezing- 
point, or nearly four degrees higher than at Milan, Pavia, 
Padua, and all Lombardy, where the mean heat of the year 
reaches 55°. In the Orkney Islands, at Stromness, a little to 
the south of Stockholm (there is not one degree difference in 
their latitudes), the mean winter temperature is 7°, or higher 
than that of London or Paris. Stranger still, the inland 
waters of the Faroe Islands never freeze, situated in 62° of 
north latitude, beneath the mild influences of the west wind 
and the sea. Upon the coast of Devonshire, one part of 
which has been termed the Montpellier of the North, because 
of the mildness of its climate, the Agave Mexicana has been 
known to flower when planted in the open air, and orange- 
trees trained upon the wall to bear fruit, though only scantily 
protected by a thin matting. 

" There, as at Penzance, Gosport, Cherbourg, and the coast 
of Normandy, the mean temperature of the winter is 42°, 
being but 18.5° below that of Montpellier and Florence." 



CLIMATE AS INFLUENCED BY THE FOREST. 127 



XIII. CLIMATE AS INFLUENCED BY 
THE PRESENCE OF THE FOREST. 

When sunshine falls on an area covered by trees, 
the heat is more thoroughly absorbed or taken in 
than when it falls on an arid or uncovered surface. 

The more thorough absorption of heat by a 
wooded area is caused mainly as follows : 

1. The greater extent of surface presented by a 
wooded than by an unwooded area, not only by 
the trees themselves, but often also by the under- 
brush which exists in most forest regions. 

2. The porous and better absorbing character 
of the carpet of leaves that generally covers the 
ground in forest regions. 

3. The presence of a greater amount of moisture 
in the air of a forest region than in a region that 
is void of vegetation. 

The marked increase in the area of a surface 
covered by a forest over that of an equally large 
unwooded surface would itself, apart from any 
other circumstances, necessitate a smaller rise or in- 
crease of temperature in the forest than would the 



128 OUTLINES OF FORESTRY. 

same quantity of the sun's heat falling on an equal 
area of bare ground. Therefore, the sun's heat 
when permitted to fall on a forest region is more 
thoroughly absorbed, is spread over a greater sur- 
face, and penetrates the ground more thoroughly 
than it would if thrown on bare ground. For, 
when the rays fall on a bare, dry, parched surface, 
the}' penetrate the ground to but a small depth, 
and heating a smaller amount, must necessarily 
produce a greater increase of temperature. 

The same is true as regards the loss of heat: 
forest districts, which take in heat slowly, part 
with it slowly; while bare, uncovered surfaces, 
which take in heat quickly, part with it quickly. 

It, therefore, follows that since the forests do not 
rapidly heat, they do not become excessively hot 
in summer; and, since they part with their heat 
slowly, they do not become very cold in winter. 

The fact that an area covered with forests does 
not tend to become as cold in winter as bare, 
uncovered ground, exerts a great influence on the 
depth to which the frost extends downwards. 

The non-conducting power for heat of even a 
very thin layer of snow is well known. If snow 
falls before the frost penetrates the ground to any 
great depth, it will act as a covering to prevent the 



CLIMATE AS INFLUENCED BY THE FOREST. 129 

earth from losing heat. The frost will, therefore, 
be prevented from entering the ground to any great 
depth. In the temperate regions of the Northern 
Hemisphere, in districts covered by forests, the 
early snows of winter are, for the greater part, apt 
to fall before the ground is frozen to any con- 
siderable depth. In the early spring, when the 
thaws come, the water derived from the melting 
of the ice and snow can then drain quietly into the 
ground and fill the reservoirs of the springs. 

If, however, the forests are removed, the ease 
with which the ground loses its heat generally per- 
mits it to freeze before the first snow falls, and the 
non-conducting power of the layer of snow causes 
the ground to remain frozen until long after the 
spring thaws have melted the snow. Under such 
circumstances, the water derived from the melting 
snow rapidly drains almost entirely off the sur- 
face, and is apt to produce disastrous floods. 

Tyndall has shown that the ability of air to be- 
come heated, by absorbing heat directly from the 
sun's rays as they pass through it, depends almost 
entirely on the presence of water vapor. The air 
over a forest district is necessarily more moist, and 
consequently better able to absorb heat and become 
heated than the air over a dry, barren tract. 



130 OUTLINES OF FORESTRY. 

Moist air, moreover, is not only better able to 
absorb the beat accompanying the direct rays of 
the sun, but is especially able to absorb that kind 
of heat which is thrown oft* from the heated earth. 
Consequently, the air over a forest district absorbs 
a much larger percentage of the heat flung off 
from the heated earth than does the drier air over 
a barren district. In this way, in winter, while the 
ground is throwing oft* its heat, the moist air of 
the forest tends to remain warmer than the air 
over a dry, arid tract. 

Forests exert a marked influence on the climate 
of a country, especially at that time of the year 
when the crops are liable to suffer injury from 
early frosts. 

The ease with which bare or poorly covered 
ground throws off its heat permits such an area to 
more readily reach the temperature of the danger- 
point than would be the case if it were well 
wooded. It must be remembered that the differ- 
ence of a few degrees, or even of the fraction of a 
degree, between the air over an uncovered district, 
and the air over a covered district in the forest, 
may make all the difference between the occurrence 
of frost and its non-occurrence. It is, indeed, often 
but the difference of a fraction of a degree, that 



CLIMATE AS INFLUENCED BY THE FOREST. 131 

may cause by an early frost the loss of millions of 
dollars to an agricultural district. 

Again, it is in the late autumn, at the time of the 
early frosts which are so feared in the agricultural 
districts, that a vegetable covering may be able to 
fling back to the earth sufficient heat thrown out 
by the cooling ground to prevent the temperature 
of the air immediately around growing plants 
from reaching the freezing-point. 

Forests exert a sheltering action at the time of 
frosts in keeping the land to the leeward warmer 
than that to the windward. Not only do they 
act as an actual barrier or screen, sheltering and 
protecting the land immediately to the leeward 
side, but this protecting action extends to a much 
greater distance beyond the immediate neighbor- 
hood of the forest than might be supposed. 

The leaves of almost any forest tree, when ex- 
amined under the microscope, show greatly ex- 
tended surfaces in the shape of irregularities, or 
spine-like projections. These extended surfaces 
aid the tree greatly in throwing off from the very 
slightly heated earth the stores of heat which it 
possesses, even in the depth of winter, and which, 
thus passing into the air, tend to prevent a too 
marked fall of temperature during winter. 



132 OUTLINES OF FORESTRY. 

Generally, the air of the forest is cooler and 
damper in summer than the air over the open 
fields in the same district. 

1st. Because the air of the forest is shielded 
from the direct rays of the sun. 

2d. Because the air is chilled by evaporation from 
the moister ground. 

A large tract of forest in any section of country 
tends to prevent marked changes in its climate, as 
compared with those that occur in the same region 
over the open fields. 

1. By permitting the wooded area to more thor- 
oughly absorb the sun's heat on account of the 
greater surface it presents. 

2. By keeping the air moister and, therefore, 
better able to absorb the sun's heat. 

3. By acting as a screen to the land to the lee- 
ward of a cold wind. 

4. By preventing the frost from penetrating the 
ground to too great a depth before protected by a 
covering of snow. 

Geikie, in his " Text-Book of Geology," * in 



* Keprinted, by permission, from " Text-Book of Geology," 
by Archibald Geikie, LL.D., F.B.S. London : Macmillan & 
Co., 1882. Pp. 971. 



CLIMATE AS INFLUENCED BY THE FOREST 133 

referring to the manner in which man may influ- 
ence the climate of any particular part of the 
earth, says on page 471 : 

" Human interference affects meteorological conditions : 1, 
by removing forests and laying bare to the sun and winds 
areas which were previously kept cool and damp under trees, 
or which, lying on the lee side, were protected from tempests ; 
as already stated, it is supposed that the wholesale destruction 
of the woodlands formerly existing in countries bordering the 
Mediterranean has been in part the cause of the present desic- 
cation of these districts ; 2, by drainage, the effect of this 
operation being to remove rapidly the discharged rainfall, to 
raise the temperature of the soil, to lessen the evaporation, and 
thereby to diminish the rainfall and somewhat increase the 
general temperature of a country ; 3, by the other processes 
of agriculture, such as the transformation of moor and bog 
into cultivated land, and the clothing of bare hill-sides with 
green crops or plantations of coniferous and hard-wood trees." 

Not only does the forest prevent the excessive 
heating of the land on which it grows, and there- 
fore similar excessive heating of the air over the 
land, by the greatly extended surface the trees and 
undergrowth present to the sun's rays, but it also 
acts by the direct absorption of the sun's rays 
to cause the separation of the carbon from the 
oxygen in carbonic acid, and the hydrogen from 

the oxygen in the water in the vegetable king- 

12 



134 OUTLINES OF FORESTRY. 

dom. Tyndall, in his " Heat as a Mode of Mo- 
tion," * page 529, says : 

" In the building of plants, carbonic acid is the material 
from which the carbon of the plant is derived, while water is 
the substance from which it obtains its hydrogen. The solar 
rays wind up the weight. They sever the united atoms, set- 
ting the oxygen free, and allowing the carbon and the hydro- 
gen to aggregate in woody fibre. If the sun's rays fall upon 
a surface of sand, the sand is heated, and finally radiates 
away as much heat as it receives. Let the same rays fall upon 
a forest ; then the quantity of heat given back is less than 
that received, for a portion of the sunlight is invested in the 
building of the trees. We have already seen how heat is con- 
sumed in forcing asunder the atoms of bodies, and how it 
reappears when the attraction of the separated atoms comes 
again into play. The precise considerations which we then 
applied to heat, we have now to apply to light, for it is at the 
expense of the solar light that the chemical decomposition 
takes place. Without the sun, the reduction of the carbonic 
acid and water cannot be effected ; and, in this act, an amount 
of solar energy is consumed, exactly equivalent to the molecu- 
lar work done." 

Concerning the influence of the forests on cli- 
mate, Hough, in his report to the United States 

* Reprinted, by permission, from " Heat as a Mode of 
Motion," by John Tyndall, F.R.S., LL.D. New York: 
D. Appleton & Company, 5 Bond Street, 1883. Pp. 591. 



CLIMATE AS INFLUENCED BY THE FOREST 135 

Commissioners of Forestry for 1877, quoting from 
a paper by M. A. C. Becquerel, on the " Climatic 
Effects of Forests," * page 310, says : 

" The forests exercise in many ways an influence upon the 
climate, but to understand this we must define what we under- 
stand by climate. 

" The climate of a country, according to M. Humboldt, is 
the combination of calorific, aqueous, luminous, serial, electri- 
cal, and other phenomena, which fix upon a country a definite 
meteorological character that may be different from that of 
another country under the same latitude and with the same 
geological conditions. According as one or another of these 
phenomena predominate we call the climate warm, cold, or 
temperate, dry or humid, calm or windy. 

" We always regard heat as exercising the greatest influence, 
and after this the amount of water falling in different seasons 
of the year, the humidity or dryness of the air, prevailing 
winds, number and distribution of storms throughout the year, 
clearness or cloudiness of the sky, the nature of the soil and 
vegetation which covers it, and, according as it is natural or 
the result of cultivation, the following questions arise for 
consideration : 

" 1. What is the part that forests play as a shelter against 
the winds or as a means of retarding the evaporation of rain- 
water ? 

* Eeprinted, by permission, from a " Eeport upon Forestry," 

1877, by Franklin B. Hough. Washington Printing-Onice, 

1878. Pp.650. 



136 OUTLINES OF FORESTRY. 

" 2. What influence do the forests exert, through the absorp- 
tion of their roots or the evaporation of their leaves, in modi- 
fying the hygrometrical conditions of the surrounding atmos- 
phere ? 

" 3. How do they modify the temperature of a country ? 

" 4. Do the forests exercise an influence on the amount of 
water falling, and upon the distribution of rain throughout 
the year, as well as upon the regulation of running waters and 
springs ? 

" 5. In what manner do they intervene in the preservation of 
mountains and slopes ? 

" 6. Do the forests serve to draw from the storm-clouds their 
electricity, and by thus doing diminish their effects upon the 
neighboring regions not wooded ? 

" 7. What is the nature of the influence that they may be 
able to exercise upon the public health ? 

" From these questions we may see what questions we must 
solve before being able to decide as to the influence that the 
clearing off of woodlands may exercise upon the climate of a 
country." 

Much valuable data concerning the results of 
the destruction of the forests on climate, rainfall, 
and other meteorological conditions, were collected 
by several scientific expeditions sent to Brazil 
under the direction of Louis Agassiz. 

In an account of the Thayer expedition in 1865 
and 1866, Professor Hartt, in a description of the 
" Geology and Physical Geography of Brazil," * 
page 319, thus refers to the marked effects that have 



CLIMATE AS INFLUENCED BY THE FOREST. 137 

been produced by the wholesale destruction of the 
forests by the burning over of their former areas, — 

" The limits of the forests, of the belt of decomposition, 
and of the area over which copious rains fall, coincide very 
remarkably, and show a dependence upon each other, but the 
forest belt has a smaller area than that of decomposition or of 
the rains. The wooded belt seems to have narrowed greatly 
within comparatively recent times, losing its foothold in the 
west, where immense regions, now campos, over which the 
climate and soil would normally be proper for the growth of 
forests, have dried up, the climate has become hot, less rain 
now falls, and the forest cannot regain its lost place. Doubt- 
less there are many natural physical causes to be taken into 
consideration in studying the distribution of the forest, catinga, 
and campos florae ; but there is one agency that has been at 
work in Brazil whose effects we can hardly over-estimate, and 
that is the burning over of the wood and campos lands by 
man. The very physical features of the highlands of Brazil 
determine a difference in the luxuriance in the florae of differ- 
ent regions, and there are, as I have already shown, regions 
where for ages the climate has been such that forests could 
scarcely have had any noteworthy extension, so that there must 
have always been in Brazil, naturally, virgin forests, catingas, 
campos, and barrens. On the coast, where the forest is dense 
and moist, and the climate is wet, forest fires are next to 



* Eeprinted, by permission, from " Scientific Eesults of a 
Journey in Brazil," by Ch. Fred. Hartt. Boston : Field, Os- 
good & Co., 1870. Pp. 620. 

12* 



138 OUTLINES OF FORESTRY. 

impossible, and one never sees a scorched and dead wood, such 
as covers so large an area in the province of New Brunswick, 
for instance. But in the interior, where the catinga forests 
drop their leaves, and are dead for several months in the dry- 
season, fires are easily kindled and the wood killed; and 
fires set in open fields or campos, for the purpose of pro- 
ducing a new crop of grass, may spread to the neighboring 
catingas. It is the opinion of many writers that a large part 
of the catinga and campos regions of the Brazilian highlands 
was once covered by forests, and that their present bare ap- 
pearance and the character of their florae is in a very great 
measure due to frequent and extensive burning over of the 
country. Every year the Brazilian campos lands are sys- 
tematically and almost entirely burned over, for the purpose 
of producing a new crop of grass. This burning, of course, 
has destroyed all those trees and shrubs and plants of all 
kinds that cannot bear the scorching, and has wrought a great 
alteration in the character of the whole flora of the region ; 
the climate also has suffered a change, for with the destruction 
of the woods and forests it becomes hotter, the unprotected 
earth is like a furnace, streams run diy a few days after a 
shower, and the springs disappear." 

The following geographical instances of the 
effects of forests on climate are referred to by 
Becquerel in a previous quotation. 1 



* 



* Eeprinted, by permission, from " Report upon Forestry," 
1877, by Franklin B. Hough. Washington : Government 
Printing-Office, 1878. 



CLIMATE AS INFLUENCED BY THE FOREST. 139 

St. Helena. 

Fully forested when discovered in 1502. The introduction 
of goats and other causes led to the removal of its forests. 
Heavy floods and severe droughts were the result ; replanting 
of forest trees towards the close of 1700 resulted in a more 
uniform rainfall and its better distribution. Subsequent de- 
structions of the forest have again brought back the original 
condition of affairs. 

Island of Ascension. 

When discovered in 1815 it was barren, and so destitute 
of water that supplies were brought to it from the mainland. 
The effects of planting trees resulted in an increased rainfall, 
from 10.18 in 1858 to 25.11 in 1863. It now grows forty kinds 
of trees, where but one grew in 1843 for want of water. 



140 OUTLINES OF FORESTRY. 



XIV. PURIFICATION OF THE ATMOS- 
PHERE. 

The atmosphere covers the earth's surface as a 
vast ocean of air that extends upwards for a dis- 
tance of several hundred miles. 

It is composed mainly of a mixture of two gas- 
eous substances, — namely, of nearly seventy-seven 
per cent, by weight of nitrogen and about twenty- 
three per cent, of oxygen. Besides these there is 
a nearly constant quantity of carbonic acid gas, 
and a variable quantity of the vapor of water. 

The carbonic acid is nearly in the proportion of 
four parts to ten thousand of air ; or very nearly 
one cubic inch of carbonic acid gas to each cubic 
foot of ordinary air. 

The different ingredients of the atmosphere 
serve various purposes in the economy of the 
earth. 

The oxygen is necessary for the existence of 
animal life. 

The carbonic acid is necessary for the existence 
of plant life. 



PURIFICATION OF THE ATMOSPHERE. 141 

The moisture of the air is necessary for the 
existence of both animal and plant life, although, 
perhaps, it is more necessary for the existence of 
plant life. 

Every action of an animal results in the decay 
and subsequent death of some part of its body, 
Although this death does not take place immedi- 
ately, yet the use of any part or member of the 
body results in its waste and subsequent death. 
In order to replace these dead parts some form 
of nourishment is necessary. This nourishment 
comes from the food of the animal, which, by the 
process of digestion, goes to make up the blood. 
The blood carries to the parts of the body which 
require nourishment the materials needed for sub- 
sequent growth, and, at the same time, takes away 
or carries off the dead or decaying parts. 

The blood is forced through the different parts 
of the body by the action of the heart, which acts 
like a force-pump. The blood goes to these parts 
of the body as bright red arterial blood. It leaves 
them so clogged with dead and decaying parts, 
that it becomes changed into a dark, bluish-black, 
venous blood. 

The oxygen of the air is, in general, necessary 
to the existence of animal life in order to burn 



142 OUTLINES OF FORESTRY. 

out or remove from the blood these dead and 
decaying parts, and so change the dark, venous 
blood to bright red arterial blood. 

The oxygen brings about this change mainly by 
combining with and slowly burning the waste 
products so as to form water vapor and carbonic 
acid gas. 

If there was nothing to oppose this action of 
animal life all the oxygen would, in the end, be 
removed from the air and changed into carbonic 
acid gas, and no further animal life would be pos- 
sible on the earth. Plants, however, during their 
growth, in the presence of sunshine, take in or 
absorb carbonic acid gas. In the delicate structure 
of the leaf this gas is broken up into carbon, 
which is retained by the plant to form its woody 
fibre, and into oxygen, which is given off and 
passes into the atmosphere. 

Plants, therefore, during active growth take in 
carbonic acid gas and give out oxygen. 

A wonderful balance is thus maintained in na- 
ture, and the composition of the atmosphere is 
kept practically constant. 

What animals reject, plants need for their ex- 
istence. "What plants reject, animals need for their 
existence. It is like the case of the renowned 



PURIFICATION OF THE ATMOSPHERE. 143 

Jack Sprat and his wife, of nursery lore, who 
between them kept both plate and platter clean. 
Each liked and thrived on what the other re- 
jected. 

If this balance between the plant and animal 
kingdom is disturbed, the composition of the 
atmosphere will be altered, and a marked change 
will be produced in the earth's plant and ani- 
mal life. Such changes have been observed in 
the geological past long before the creation of 
man. 

The earth's atmosphere was originally vaster 
than at present. The quantity of oxygen and 
carbonic acid gas was enormously greater. 

A careful estimate places the amount of oxygen 
that exists, combined with the different substances 
that form the fifteen or twenty miles of the earth's 
crust that have been carefully studied, at least at 
one-half of the total weight. 

At an early age in the earth's life this oxygen 
existed in a free state in the atmosphere, and be- 
came fixed by combining with or oxidizing the 
different materials of the crust. This oxidizing 
action has now practically ceased, and the quantity 
of oxygen present in the air is constant. 

Prior to the Carboniferous age carbonic acid 



144 OUTLINES OF FORESTRY. 

must have existed in the air in enormous quanti- 
ties ; for, the vast deposits of carbon, which form 
the coal-beds now found in the different parts of 
the crust, then existed in a gaseous condition in 
the atmosphere combined with oxygen. 

Animal life of the present type was impossible 
in the unpurified atmosphere that existed before 
the Carboniferous age. The conditions were, how- 
ever, such as to favor dense and luxuriant plant 
life, and at no time in the world's history, either 
before or since, has such luxuriant vegetable 
growth existed. 

A twofold action of purification was effected by 
the plants of the Carboniferous period ; namely, 
the separation of the carbon and the liberation of 
the oxygen. 

The exact balance between the plant and ani- 
mal life of the earth, so carefully established 
by nature, cannot be disturbed without marked 
changes in the entire races of animals and plants 
that now exist. 

The thoughtless and unnecessary removal of the 
forests from over extended areas will not only dis- 
turb the balance during the time such surfaces are 
bare, but since, in many cases, such removal per- 
mits this section of country to be denuded of its 



PURIFICATION OF THE ATMOSPHERE. 145 

soil, there will also follow a permanent disturbance 
from the inability of such section of country to 
sustain any plant life. 

As to the purification of the atmosphere by 
plants, Dana, in his " Manual of Geology," * says, 
on page 353, — 

" In the present era, the atmosphere consists essentially of 
oxygen and nitrogen, in the proportion of twenty-three to 
seventy-seven parts by volume. Along with these constitu- 
ents, there are about four parts by volume of carbonic acid in 
ten thousand parts of air. Much more carbonic acid would 
be injurious to animal life. To vegetable life, on the contrary, 
it would be, within certain limits, promotive to growth ; for 
plants live mainly by means of the carbonic acid they receive 
through their leaves. The carbon they contain comes princi- 
pally from the air. 

" This being so, it follows, as has been well argued, that the 

carbon which is now coal, and was once in plants of different 

kinds, has come from the atmosphere, and, therefore, that the 

atmosphere now contains less carbonic acid than it did at the 

beginning of the Carboniferous period, by the amount stowed 

away in the coal of the globe. 
******** 

" Such an atmosphere, containing an excess of carbonic acid 
as well as of moisture, would have had greater density than 

* Eeprinted, by permission, from a " Manual of Geology," 
third edition, by James D. Dana. New York : Ivison, Blake- 
man, Taylor & Co. London : Triibner & Co. Pp. 911. 
q k 13 



146 OUTLINES OF FORESTRY. 

the present ; consequently, as urged by E. B. Hunt, it would 
have occasioned increased heat at the earth's surface, and this 
would have been one cause of a higher temperature over the 
globe than the present. 

" During the progress of the Carboniferous period there was, 
then, (1) a using up and storing away of the carbon of the 
superfluous carbonic acid, and, thereby, (2) a more or less per- 
fect purification of the atmosphere, and a diminution of its 
density. In early time there was no aerial life on the earth ; 
and, so late as the Carboniferous period, there were only rep- 
tiles, myriapods, spiders, insects, and pulmonate mollusks. 
The cold-blooded reptiles of low order of vital activity, cor- 
respond with these conditions of the atmosphere. The after- 
ages show an increasing elevation of grade and variety of 
type in the living species of the land." 



HAIL. 147 



XV. HAIL. 

Hail occurs at times when great differences of 
temperature exist between neighboring masses of 
very moist air. 

By permitting great differences of temperature 
to occur, the destruction of the forest is, in many 
cases, followed by an increase in the number and 
severity of hail-storms. 

In order to understand the manner in which the 
destruction of the forest may influence the occur- 
rence of hail-storms, it will be necessary to study 
some of the peculiarities of such storms and to re- 
view what are now generally believed to be their 
causes. 

Although hail may fall at any time of the year, 
yet it occurs most frequently in summer towards 
the close of a very warm day. 

The exact causes which produce hail are not 
known. The conditions necessary for its occur- 
rence appear to be the rapid mixture of very warm 
and very cold moist air. 

A hail-storm is generally preceded by the appear- 



148 OUTLINES OF FORESTRY. 

ance of several layers of dark, grayish, clouds. In 
most all cases, before the beginning of a hail-storm, 
a violent movement is seen to take place between 
these layers, apparently of a whirling character. 
Generally, too, hail-storms are attended by violent 
disturbances in the electrical equilibrium of the 
atmosphere, as is evidenced by the frequent dis- 
charge of the lightning-bolt and the almost con- 
tinual roar of thunder. Then follows a fall of 
hailstones, the size of which is much larger at the 
beginning and towards the middle of the storm 
than towards the close. Towards the close of the 
storm, however, the quantity of hail which falls is 
greatest. 

If a hailstone be examined by cutting it in two, 
it will be seen to consist of alternate layers of ice 
and snow laid over one another in successive coats 
like the layers of an onion. A cross-section of a 
hailstone can be made by holding it against the 
surface of a hot plate until half of the stone has 
been melted away. 

Hailstones vary in weight from a few grains to 
several pounds. Records exist of hailstones weigh- 
ing many pounds, sometimes of even several hun- 
dred pounds. In such cases, however, it is more 
than probable that the stones were produced by 



HAIL. 149 

the regelation, or freezing together, of numerous 
smaller stones, as follows : 

The excessive fall of small hailstones, that oc- 
curs towards the close of the storm, often produces 
heaps of hailstones several feet in thickness. The 
separate hailstones readily freeze together, and are 
afterwards cut into smaller masses by the action 
of the water rapidly draining off the earth. The 
fragments thus formed, in all probability, give rise 
to stories of mammoth hailstones. 

The severity of the lightning-flashes, which at- 
tend nearly all great hail-storms, has led some 
meteorologists to believe that hail-storms are caused 
by the presence of an unusual quantity of free elec- 
tricity in the atmosphere. The electrical theory 
of hail is, however, at the present, almost entirely 
discarded, it being now generally recognized that 
the lightning is the effect of the hail-storm, and 
not its cause. 

Yolta proposed the following electrical theory 
for the production of hail. He imagined two 
approximately parallel clouds near together, the 
upper cloud formed of snow, and the under cloud 
of rain. Assuming these clouds to be respectively 
charged with positive and negative electricity, the 
particles of snow in the snow-cloud might, he 

13* 



150 OUTLINES OF FORESTRY. 

assumed, be alternately attracted and repelled into 
and from the rain-cloud, and thus receive alternate 
coatings of ice and snow until they finally fell to 
the ground as hailstones. 

In France, where the reckless destruction of the 
forest has been attended by a marked increase in 
the number and severity of hail-storms, miniature 
lightning-rods have been erected in the fields to 
prevent the occurrence of hail-storms. These 
lightning-rods either took the shape of captive 
balloons secured to the earth by tinsel threads, or 
of bundles of straw set upright in the field, or of 
metal rods permanently connected with the ground. 
Their object was to gradually discharge the air of 
its free electricity, and thus prevent the occurrence 
of hail-storms. The name of such rods, paragreles, 
is significant of their supposed action. Unfortu- 
nately, they have proved futile in action, since again 
and again the portions provided with this supposed 
protection have been as severely visited by hail- 
storms as unprotected portions. 

An endeavor has been made to explain the 
peculiar shape of hailstones by the existence of 
a number of approximately parallel clouds com- 
posed alternately of snow and rain. Drops of 
rain falling from the upper cloud would thus 



HAIL. 151 

receive successive coatings of snow and ice as they 
passed successively through the snow- and rain- 
clouds, and would finally fall as characteristically- 
shaped hailstones. 

The theory now generally received in regard to 
the formation of hailstones is, that in such storms 
the wind rotates around a vertical rather than 
around a horizontal axis. If such a whirling mo- 
tion exists between a neighboring rain- and snow- 
cloud, the particles of snow would be successively 
dipped into the rain- and snow-clouds, and would 
thus receive alternate layers of ice and snow. 

A somewhat similar theory regards a hail-storm 
as belonging to the type of the ordinary tornado. 
The whirling motion of the air is supposed to 
produce the alternate coatings of ice and snow by 
the alternate exposure of the moisture to the dif- 
ferent temperatures found in the denser and rarer 
portions of the space around which the wind is 
whirling. 

Hail-storms often cause great damage. A single 
hail-storm in France has been known to cause loss 
to the agricultural districts amounting to the sum 
of at least one million pounds sterling. 

Although the exact cause of hail-storms is at 
present unknown, yet the storms never occur 



152 OUTLINES OF FORESTRY. 

unless marked differences of temperature exist 
between neighboring portions of the air. The 
removal of the forest from any considerable section 
of country permits such differences of tempera- 
ture to occur. In point of fact, it has been no- 
ticed in parts of the world from which the forests 
have been removed, that the number and severity 
of hail-storms have undoubtedly increased. 

Destructive hail-storms may therefore be re- 
garded as one of the evil results which naturally 
follow the destruction of the forest. 

As regards the supposed protective influence 
of lightning- or hail-rods against destructive hail- 
storms, Loomis, in his " Treatise on Meteorology," * 
writes on page 135 : 

" It has been proposed to preserve the vineyards and valua- 
ble farms from the ravages of hail by erecting an immense 
number of poles, armed with iron points, communicating with 
the earth, for the purpose of drawing off the electricity of the 
clouds. Multitudes of these hail-rods were erected in Switzer- 
land, but without the expected success. 

" It is believed that electricity performs altogether a subordi- 
nate, if not an unimportant part in the formation of hail ; 

* Reprinted, by permission, from " A Treatise on Meteo- 
rology," by Elias Loomis, LL.D. New York: Harper & 
Brothers, Franklin Square, 1868. Pp. 305. 



HAIL. 153 

and if we could draw off all the electricity from the hail-cloud 
as fast as it was generated, it is not improbable that the hail 
would be formed about as large and as abundantly as at present. 
" But, even supposing electricity to be the sole agent in the 
production of hail, hail-rods could not be expected to furnish 
security against hail unless an entire continent could be studded 
thick with them, for in the middle latitudes the hail-cloud ad- 
vances eastward with a velocity sometimes of forty or more miles 
per hour, and the hailstones which fall in one locality are those 
which were forming when the cloud was many miles westward 
of that point ; so that, to protect a small spot, the whole coun- 
try for many miles westward should be armed with rods ; and 
it is conceivable that a hail-cloud arriving over a region studded 
with these rods might immediately pour down a large quantity 
of hailstones which would have fallen farther eastward if the 
rods had not discharged the electricity of the cloud." 

The following description of a hail-storm that 
occurred near Bordeaux, France, in 1865, is thus 
given by Flammarion, in his work entitled " The 
Atmosphere," * page 393. 

" On May 9, 1865, for instance, a storm began at 8.30 a.m. 
over Bordeaux and proceeded in a N.N.E. direction, passing 
over Perigueux at 10 a.m., Limoges at noon, Bourges at 2 
P.M., Orleans at 5.30 p.m., Paris at 7.45 p.m., Laon at 11 p.m., 
and collapsing a little after midnight in Belgium and the North 

* Eeprinted, by permission, from " The Atmosphere," by 
Chamille Flammarion. New York: Harper & Brothers, 
Franklin Square, 1873. Pp. 454. 



154 OUTLINES OF FORESTRY. 

Sea. Its mean breadth was from fifteen to twenty leagues. 
The hail only fell in certain places : to the left of Perigueux, 
over the arrondissement of Limoges, to the right of Chateau- 
roux, to the southeast of Paris, from Corbeil to Lagny, and in 
the arrondissements of Soissons and Saint-Quentin. At this 
latter point it was of a formidable character. The crystal mass 
which fell from the sky upon the Catelet meadows formed a 
bed a mile and a quarter long and two thousand feet broad, 
estimated to amount altogether to twenty-one millions of cubic 
feet. The hailstones did not disappear for more than four 
days afterwards. These hailstones sometimes destroy all the 
crops, as, for instance, that which occurred in the neighbor- 
hood of Angouleme on August 3, 1813. The day had been 
fine, and the wind was due north until 3 p.m., when it sud- 
denly veered right round ; the sky gradually became covered 
with clouds, which, collecting one on the top of the other, 
offered a terrible spectacle. The wind, which from noon until 
5 p.m. had been rather violent, suddenly dropped. Thunder 
was heard in the distance, and gradually became louder ; the 
sky, at last, became totally obscured, and at 6 p.m. there was 
a tremendous fall of hail, the stones being as large as eggs. 
Several persons were severely wounded, and a child was killed 
near Barbezieux. The next day the ground looked as it might 
do in midwinter : the hailstones had accumulated in the hol- 
lows and the roads to a height of thirty to forty inches ; trees 
were entirely stripped of their leaves ; vines were cut into 
pieces, the crops crushed, the cattle, sheep, and pigs especially 
were severely injured. The whole neighborhood was deprived 
of game, and some few young wolves were found dead. The 
effects of the storm were still visible in 1818." 



REFORESTATION AND TREE-PLANTING. 155 



XVI. REFORESTATION AND TREE- 
PLANTING. 

By reforestation is meant the replanting of trees 
in any locality from which they have been removed 
either accidentally or purposely. 

"Where the removal of the forests has been 
made in a hap-hazard way, and no care has been 
taken to protect the soil from the effects of rapid 
drainage, the loss of the soil in some cases is so 
great as to render the area not only unable to sus- 
tain trees of the same character as those which 
have been removed, but even to render it unable 
to sustain any trees whatever. If, however, in the 
removal of the trees, care has been taken that the 
loss of soil is but trifling, it may be possible to 
again reclothe the surface with trees similar to 
those which have been removed. 

The French term for this process of replacing 
forests is reboisement. Our English word reforesta- 
tion may be safely taken as its equivalent. 

The object of reforestation is to avoid the evils 
which result from the removal of the forests by 



156 OUTLINES OF FORESTRY. 

perpetually maintaining forest tracts in portions 
of the earth set aside for such purposes. 

"Where the loss of the soil following the destruc- 
tion of the forests has been too marked to permit 
the successful replanting of trees, some of the evil 
effects following rapid drainage, such, for exam- 
ple, as disastrous floods, with their consequent 
droughts, have been in a measure lessened by re- 
planting the bare surface with different species of 
hardy grasses, which, by absorbing and holding 
the rain, permit the water to drain slowly off the 
surface. 

The time required for the full growth of forest 
trees is so great that, unless considerable encour- 
agement is given to the planting of trees, reforesta- 
tion will scarcely be attempted to any considerable 
extent. In most cases where reforestation has been 
attempted, laws have been enacted offering certain 
premiums, either in land or in money, for success- 
ful tree-planting. 

Where reforestation is carried out on a large 
scale, under the encouragement of a government, it 
is desirable that either seeds or seedlings be sup- 
plied by the government, or that extensive nur- 
series be established. Great care must be taken 
to insure the planting of the varieties of trees best 



REFORESTATION AND TREE-PLANTING. 157 

suited to exist in the particular section of country 
that is to be reforested. 

Since those sections of country where reforesta- 
tion is to be attempted have already, by the removal 
of the forests, been exposed to the loss of soil, 
great care must be taken in the replanting of trees 
not to needlessly disturb the soil. Two methods 
may be employed in reforestation, — viz. : 

1. Sowing. 

2. Tree-planting. 

Considerable difference of opinion exists as to 
which of these two methods is preferable. Un- 
questionably, however, each is best suited for par- 
ticular cases, and, in point of fact, each has been 
adopted with considerable success in different parts 
of the world. 

Seeding can, perhaps, be most profitably fol- 
lowed in the temperate latitudes, in situations 
where the growth of the tree is comparatively 
certain. In higher latitudes the planting of trees 
is, perhaps, preferable, since the germination and 
continued growth of the seeds are by no means so 
certain. 

In the case of the destruction of the forest by 
avalanches, replanting or reforestation is rendered 
much more difficult by the fact that the soil, in 

14 



158 OUTLINES OF FORESTRY. 

such cases, is often so almost entirely removed by 
the force of the rushing snow that little but the 
bare rocks remain. 

In Italy, laws passed in 1877, set aside the fol- 
lowing classes of lands as suitable for being in- 
cluded under the provisions of the forest regula- 
tions, — namely : 

Forest lands on mountain-sides, or in such 
places as might, from their location, by the loss of 
their trees, cause injury to the lowlands by ava- 
lanches, or that might, by their drainage, influence 
or modify the water-courses. 

It is generally recognized in some of the west- 
ern portions of the United States, that when trees 
are planted in plots around the farm lands, or on 
the sides of such lands, the protection thus af- 
forded the rest of the land against the winds is 
greater in actual money value than the rent of the 
ground occupied by such forests. 

Whenever reforestation is attempted over ex- 
tended areas, care should be taken as to the por- 
tions which are best suited for such purposes. 

It would seem that the following locations are 
especially adapted as being suited for the perpetual 
maintenance of forests on them, — namely: 

1. Wetlands. 



REFORESTATION AND TREE-PLANTING. 159 

2. Lands covered with thin soil. 

3. Lands covered with a rather poor soil. 

4. Along the margins of all rivers, wherever 
the land is not actually required for purposes of 
roads or other public uses. 

5. On the sides of all mountain-slopes, where 
the soil is of the proper character. 

6. On the slopes of all mountains subject to 
avalanches. 

The following translation of the French laws of 
1860 for reforestation is taken from the report 
of the United States Commissioners for 1877,* 
page 338 : 

French Code of Keboisement of Mountains, July 
28, 1860. 

"Article 1. Subventions may be allowed to communes 
and public bodies, or to individuals, for replanting lands on 
the tops or slopes of mountains. 

" Article 2. These aids may consist either in the delivery 
of seeds, or plants, or in premiums in money. In those given 
by reason of the work done for the general good, and in cases 
of communes and public bodies, regard is to be had to their 
resources, and the sacrifices they must make, and to their need, 
as also to the sums given by general councils for reboisement. 

* Eeprinted, by permission, from a " Eeport upon Forestry," 
1876, by Franklin B. Hough. Washington: Government 
Printing-Office, 1878. Pp. 649. 



160 OUTLINES OF FORESTRY. 

" Article 3. Premiums in money given to individuals can- 
not be paid until after the work is done. 

Article 4. In cases where the public interests demand that 
the works of reboisement should be made obligatory, either 
on account of the condition of the soil, or the dangers that 
may happen to the lands below, proceedings are to be had 
as follows : 

" Article 5. An imperial decree, issued in council of state, 
declares the public utility of the works, fixes the boundaries 
of land in which it is necessary to execute the reforesting, 
and the time within which it must be done. This decree is 
preceded (1) by an open inquiry in each of the communes 
interested ; (2) by a deliberation in the municipal councils of 
these communes, in conjunction with those most important ; 
(3) the advice of a special commission, composed of the pre- 
fect of the department or his delegate, a member of the gen- 
eral council, a member of the council of arrondissement, an 
engineer of bridges and roads or of mines, a forest-agent, and 
two landholders of the commune interested ; (4) the advice of 
the council of arrondissement, and that of the general council. 

" The prods-verbal specifying the lands, the plan of the places, 
and the project of the works prepared by the forest adminis- 
tration, with the concurrence of an engineer of bridges, roads, 
or of mines, are to be deposited in the office of the mayor 
during the inquiry, the duration of which is one month, be- 
ginning with the publication of the prefectoral order, which 
prescribes the opening of the inquest and the meeting of the 
municipal council. 

"Article 6. The imperial decree is to be published and 
posted up in the communes interested. The prefect is also to 



REFORESTATION AND TREE-PLANTING. 161 

notify the communes and public bodies, as well as individuals, 
by an extract of the imperial decree, concerning the indications 
relating to the lands belonging to them. The act of notification 
shall show the limit of time allowed for the work of reboise- 
ment, and if there is occasion, the offer of aid from the admin- 
istration on the advances it is disposed to make. 

" Article 7. If the lands included within the limits fixed 
by the imperial decree belong to individuals, the latter are to 
declare whether they will undertake to do the replanting 
themselves; and, if so, they are to be held to execute the 
work within the time fixed by the decree. In case they 
refuse or fail to perform agreement, proceedings may be had 
for their expropriation, on the ground of public utility, ob- 
serving the formalities prescribed under Title II. and fol- 
lowing, of the law of May 3, 1841. The proprietor expro- 
priated in the execution of this article has the right to re- 
gain possession of his property after reboisement, subject to 
payment of charges for expropriation, the cost of labors in 
principal and interest. He may relieve himself of the price 
of the labors by relinquishing half of the property. If the 
proprietor wishes to obtain repossession, he should make a 
declaration to the sub-prefect within five years after notice that 
the work of reboisement has been finished, under penalty of 
forfeiture of this right. 

" Article 8. If the communes or public bodies refuse to 
execute these labors upon their lands, or if they are unable to 
do it, the state may acquire, either amicably obtaining a part 
of the lands which they will not or cannot replant, or by 
assuming sole charge of the work. In the latter case, it will 
retain the care and use of the lands until it is reimbursed its 
I 14* 



162 OUTLINES OF FORESTRY. 

advances, in principal and interest. Nevertheless, the com- 
mune shall enjoy the right to pasturage on the lands replanted 
as soon as it is found beyond risk of injury. 

" Article 9. Communes and public bodies may in all cases 
exonerate themselves from repayment to the state, by relin- 
quishing one-half of the replanted lands. This abandonment 
should be made under loss of right of doing so, within ten 
years from notice of the completion of the works. 

" Article 10. The sowing or planting cannot be made on 
more than a twentieth in one year of the surface to be planted, 
unless a resolution of the municipal councils authorizes it to 
be done to a greater extent. 

" Article 11. Forest-guards of the state may be appointed 
for the care of the sowing or planting done within the bounda- 
ries fixed by imperial decrees. Injuries proved by these guards, 
within the extent of these limits, shall be prosecuted in the 
same manner as if done in woods subject to forest regulation. 
The execution of the sentence is to be in accordance with arti- 
cles 209, 211, and 212, and paragraphs 1 and 2 of article 210 
of the Forest Code. 

"Article 12. Paragraph 1 of article 224 of the Forest 
Code is not applicable to reboisement done with aid or pre- 
miums from the state, in execution of the present law. The 
owners of lands replanted with aid or premiums of the state 
may not pasture their cattle without special license from the 
forest administration, until the time when such woods shall be 
recognized by said administration as sufficiently protected. 

" Article 13. A regulation of the public administration 
shall determine (1) the measures to be taken for fixing the 
boundaries indicated in article 5 of the present law ; (2) the 



REFORESTATION AND TREE-PLANTING. 163 

rules to be observed in preservation of works of reboisement ; 
(3) the mode of determining the advances made by the state, 
and the measures proper for assuring repayment of principal 
and interest, and the rules to be followed in the relinquish- 
ment of lands which article 9 allows communes to make to 
the state. 

" Article 14. The sum of ten million francs is appropri- 
ated for paying the expenses authorized by the present law, 
to the extent of one million a year. The minister of finances 
is authorized to sell, with right of clearing, if necessary, woods 
belonging to the state, to the value of five million francs. 

" These woods may only be taken from such as are entered 
in Table B, appended to this law. The sales shall be done in 
succession, within ten years from January 1, 1861. The min- 
ister of finances is likewise authorized to sell to communes, 
upon approved valuation, and on conditions fixed by a rule of 
the public administration, the woods hereinabove mentioned. 
The five million francs needed to complete the expenses au- 
thorized by the present law shall be provided by means of 
extraordinary cuttings, and, if necessary, from the ordinary 
resources of the budget." 



164 OUTLINES OF FORESTRY. 



XVII. THE BALANCE OF NATURE. 

For such a complex organization as the earth to 
be properly maintained in operation, an exact bal- 
ance must be preserved between its five great 
geographical forms or parts, — namely, the land, 
the water, the air, plants, and animals. So inti- 
mately are these different parts associated with one 
another, and so exact is the balance that is main- 
tained between them, that no one can be changed, 
either in amount or distribution, without markedly 
affecting all the others. 

The five geographical forms receive practically, 
entirely from the sun, all the energy by which 
they are actuated, and which activity constitutes 
the order of created things. 

A part of the heat of the sun stirs the air or 
water into vast movements called currents that 
flow between the equator and the poles. By their 
means an interchange is effected between the ex- 
cessive heat of the equatorial regions and the 
excessive cold of the poles. Another part heats 



THE BALANCE OF NATURE. 165 

the earth's surface, and causes vapor to pass off 
from the water surfaces into the atmosphere. 

Another part of the solar energy or heat is 
directly expended in maintaining one or another 
of the myriad forms of plant and animal life. 

If any of the five great geographical forms ap- 
propriates more than its share of the solar energy, 
a disturbance of the balance of nature is effected, 
which may produce far-reaching changes in the 
operation of the entire mechanism. 

Let us inquire as to some of the more evident 
ways in which this balance of nature is preserved, 
how it may be disturbed, and some of the effects 
produced by such disturbances. 

We will discuss this influence from the stand- 
point of the iive great geographical forms, — 
namely, the land, the water, the air, plants, and 
animals. 

The Land and Water. — An exact balance, both 
in the amount and distribution, of the land and 
water areas of the earth is absolutely necessary for 
the existence of the earth's present plant and ani- 
mal life. 

The total water areas of the earth are in excess 
of the land areas in about the proportion of 2J 
tol. 



166 OUTLINES OF FORESTRY. 

The most extended water areas are situated in 
the equatorial regions, the greater part of the land 
areas being situated either in the temperate or in 
the polar zones. 

At the equator, therefore, where the sun's heat 
is greatest, there exists the greatest expanse of 
water. Here are three readily-movable elements, 
the air, the water, and vapor, each of which can 
take in considerable heat without growing very 
hot. The differences between the temperature of 
the equatorial and polar regions produce vast cur- 
rents, both in the atmosphere and in the ocean, 
which effect an interchange between the excessive 
heat at the equator and excessive cold at the poles. 

Even a comparatively small change in the dis- 
tribution of the land and water areas of the earth 
would produce marked changes in its life. 

If, for example, most of the earth's surface in 
the equatorial regions was composed of land, an 
excessive temperature would be thereby produced 
that would render the equatorial regions abso- 
lutely uninhabitable by any of the present races of 
man. Consider, for example, tropical Africa. The 
equator by no means crosses this continent at its 
greatest breadth, and yet, notwithstanding the fact 
that nearly all the continent is considerably more 



THE BALANCE OF NATURE. 167 

than one thousand feet above the sea level, large 
parts of its interior are as yet absolutely unknown 
to the white man. 

What, then, would be the effect on the earth's 
present life if, instead of the present excess of 
water surface at the equator, there existed an ex- 
cess of land surface ? Beyond doubt the present 
life of the earth would be swept out of existence. 

In the same manner any marked increase in 
either the elevation or the extent of the land in 
the polar regions would be followed by such an in- 
crease in the severity of the cold as to sweep out 
of existence much of the present life of the earth. 
It was, in the opinion of most geologists, a change 
in the elevation of the polar lands that caused the 
severe cold of the glacial epoch, when most of the 
northern continents were covered with enormous 
ice-fields. 

The Air. — Any change in the composition of the 
earth's atmosphere, such, for example, as in the 
amount of its oxygen or its carbonic acid gas, 
would be followed by a change in its animal and 
plant life. 

The existence of animal life tends to decrease 
the amount of oxygen in the atmosphere, and to 
increase the amount of carbonic acid. The ex- 



168 OUTLINES OF FORESTRY. 

istence of plant life tends to increase the amount 
of oxygen and to decrease the amount of carbonic 
acid gas. 

A wonderful balance is maintained in nature as 
to the composition of the atmosphere, from the 
fact that what plants reject, animals require for 
their existence, and what the animals reject, plants 
require. 

Minerals, Plants, and Animals. — The mutual in- 
terdependence of the mineral, the plant, and the 
animal affords another illustration of the balance 
of nature. Animals obtain their food either from 
other animals or from plants. Plants, as a rule, 
live on minerals. They are so constituted as to be 
able to take the various substances directly from 
the soil, and to change them into forms that can 
be readily assimilated by animals. The continued 
existence of animals depends on the continued 
existence of plants. 

Nature has very carefully insured the presence of 
those germs or seeds that are absolutely necessary 
for the birth of either animals or plants. To in- 
sure the presence of the germs in all cases, the 
number of such germs produced is always vastly 
in excess of the number that can possibly live. In 
the case of nearly all plants and animals the num- 



THE BALANCE OF NATURE. 169 

ber of germs produced by a single individual is so 
great, that if they all lived and reproduced their 
kind at the same rate, in a very little while the 
earth itself would be too small to hold them. 

Leuwenhoek has calculated that a single speci- 
men of the domestic fly can produce seven hun- 
dred and forty-six thousand four hundred and 
ninety-six young in three months. 

According to Professor Owen, a single aphis, or 
plant louse, in the tenth generation produces one 
quintillion young. 

It has been calculated that if all the offspring 
of a single edible oyster survived for but a com- 
paratively few generations, the waters of such 
shallow inlets of the ocean as the Chesapeake Bay 
would be too small to hold them. 

In order to avoid this excessive multiplication of 
the animal and plant life of the earth, — and the 
above are but a few of the numerous similar cases 
that might be quoted, — and thus preserve the bal- 
ance of nature, which would be disturbed by such 
inordinate multiplication of any one species, all 
forms of animate creation have their natural enemies 
provided by nature to hold them in check. Those 
only continue to exist that are best fitted to exist 
under the conditions by which they are surrounded. 
H 15 



170 OUTLINES OF FORESTRY. 

The principle of the survival of the fittest plays an 
important part in preserving the balance of nature. 

Nearly every animal forms the food best fitted 
to sustain the life of some other animal. In the 
event of a too rapid multiplication of any particu- 
lar form of life, some scourge or disease appears 
which sweeps off the surplus and thus restores 
nature's balance. 

As far as careful measurements have been made, 
it can be safely assumed that the total value of the 
solar radiation is practically the same now as it 
was many thousands of years ago. Consequently, 
the total amount of energy which the earth thus 
receives from the sun, and which goes to maintain 
the present mechanism of nature, is constant. 

The distribution of this solar energy is, however, 
by no means constant. The general interchange 
that is effected between the excessive heat of the 
equator and the excessive cold of the polar regions 
may take place rapidly or slowly, and thus produce 
differences in the earth's general climate that not 
infrequently give rise to a belief in a change in 
the total heating power of the sun, when no such 
change exists. For example : 

A bare, uncovered surface heats with extreme 
rapidity, and consequently the air over it becomes 



THE BALANCE OF NATURE. 171 

intensely heated. This may give rise to an im- 
pression that the sun's heating power has in- 
creased. 

Certain causes may tend to temporarily prevent 
the free interchange of heat energy that usually 
exists between hot and cold parts of the earth. 
There will thus result an increase of temperature 
in one locality and a marked deficit in another, 
which would thus give rise to the impression that 
variations in the solar radiation existed, when, in 
reality, such variations existed. 

In the case of the evaporation of water effected 
by the sun, if the total value of the sun's heat be 
constant it might at first sight be supposed that 
the total quantity of evaporation must remain con- 
stant, and that, therefore, the total quantity of 
heat remaining the same, no change in its distri- 
bution could effect a change in the amount of the 
evaporation, and, consequently, in the value of the 
rainfall. It must be remembered, however, in this 
connection, that if circumstances existed in the 
air of any locality by which during the time of 
greatest heat the moisture was retained in the air 
of such locality, and not be removed therefrom, 
evaporation would necessarily be much smaller 
than if such moisture were removed by any cause. 



172 OUTLINES OF FORESTRY. 

The total quantity of the evaporation, therefore, 
would by no means be constant. 

It is possible, therefore, that while the existence 
of the forest over extended sections of country 
tends on the whole rather to vary the distribution 
of the rainfall through a change in the rapidity of 
the drainage, that, nevertheless, it may also, to 
some extent, tend to produce a change in the total 
quantity of the rainfall. 

The exact balance of nature that is required to 
be maintained, in order that the present life of the 
earth shall exist, can be disturbed by many means. 
In perhaps no other way does man tend more to 
disturb this balance than by the destruction of the 
forests. The removal of the forests from over ex- 
tended areas effects a disturbance of the balance 
of nature that is manifested in the following 
ways: 

1. By a marked change in the heat in summer 
and the cold of winter in the regions formerly 
covered by forests. 

2. By a marked change in the average amount 
of moisture present in the atmosphere over such 
regions. 

3. By a marked change in the character of the 
soil in such region. 



THE BALANCE OF NATURE. 173 

4. By a marked change in the drainage of such 
region. 

5. By a marked change in the number and se- 
verity of floods and droughts in such regions. 

6. By a marked change in the salubrity of the 
regions through which the rivers flow which rise 
in such districts. 

7. By a marked change in the number and 
severity of hail-storms in such regions. 

8. By an increase in the damage to the agricul- 
tural districts arising from the appearance of early 
frosts in or near such regions. 

The preservation of the forests, in at least certain 
localities, is, therefore, imperatively demanded in 
order to maintain the general balance of nature, 
and to insure on the earth a place for the com- 
fortable habitation of man. 

George P. Marsh, in his work entitled " The 
Earth as Modified by Human Action," * says on 
page 8 : 

" The revolutions of the seasons, with their alternations of 
temperature and of length of day and night, the climates of 
different zones, and the general conditions and movements of 

* Eeprinted, by permission, from " The Earth as Modified 
by Human Action," by George P. Marsh. New York : Scrib- 
ner, Armstrong & Co., No. 654 Broadway, 1874. Pp. 656. 

15* 



174 OUTLINES OF FORESTRY. 

the atmosphere and the seas, depend upon causes for the most 
part cosmical, and, of course, wholly beyond our control. 
The elevation, configuration, and composition of the great 
masses of terrestrial surface, and the relative extent and 
distribution of land and water, are determined by geological 
influences equally remote from our jurisdiction. It would 
hence seem that the physical adaptation of different portions 
of the earth to the use and enjoyment of man is a matter so 
strictly belonging to mightier than human powers, that we 
can only accept geographical nature as we find her, and be 
content with such soils and such skies as she spontaneously 
offers. 

" But it is certain that man has reacted upon organized and 
inorganic nature, and thereby modified, if not determined, the 
material structure of his earthly home. The measure of that 
reaction manifestly constitutes a very important element in 
the appreciation of the relations between mind and matter, as 
well as in the discussion of many purely physical problems. 
But, though the subject has been incidentally touched upon 
by many geographers, and treated with much fulness of detail 
in regard to certain limited fields of human effort and to 
certain specific effects of human action, it has not, as a whole, 
so far as I know, been made a matter of special observation, 
or of historical research, by any scientific inquirer. Indeed, 
until the influence of geographical conditions upon human 
life was recognized as a distinct branch of philosophical 
investigation, there was no motive for the pursuit of such 
speculations ; and it was desirable to inquire how far we have, 
or can, become the architects of our own abiding-place, ODly 
when it was known by the mode of our physical, moral, and 



THE BALANCE OF NATURE. 175 

intellectual being is affected by the character of the home 
which Providence has appointed, and we have fashioned, for 
our material habitation. 

******** 
" We cannot always distinguish between the results of man's 
action and the effects of purely geological or cosmical causes. 
The destruction of the forests, the drainage of lakes and 
marshes, and the operations of rural husbandry and industrial 
art have unquestionably tended to produce great changes in 
the hygrometric, thermometric, electric, and chemical condi- 
tion of the atmosphere, though we are not yet able to measure 
the force of the different elements of disturbance, or to say 
how far they have been neutralized by each other, or by still 
obscurer influences ; and it is equally certain that the myriad 
forms of animal and vegetable life which covered the earth 
when man first entered upon the theatre of a nature whose 
harmonies he was destined to derange have been, through his 
interference, greatly changed in numerical proportion, some- 
times much modified in form and product, and sometimes 
entirely extirpated. 

" The physical revolutions thus wrought by man have not, 
indeed, all been destructive to human interests, and the 
heaviest blows he has inflicted upon nature have not been 
wholly without their compensations. Soils to which no nutri- 
tious vegetable was indigenous ; countries which once brought 
forth but the fewest products suited for the sustenance and 
comfort of man — while the severity of their climates created 
and stimulated the greatest numbers and the most imperious 
urgency of physical wants — surfaces the most rugged and 
intractable, and least blessed with natural facilities of com- 



176 OUTLINES OF FORESTRY. 

munication, have been brought in modern times to yield and 
distribute all that supplies the material necessities, all that 
contributes to the sensuous enjoyments and conveniences, of 
civilized life. The Scythia, the Thule, the Britain, the 
Germany, and the Gaul which the Roman writers describe in 
such forbidding terms have been brought almost to rival the 
native luxuriance and easily- won plenty of Southern Italy; 
and, while the fountains of oil and wine that refreshed old 
Greece and Syria and Northern Africa have almost ceased to 
flow, and the soils of those fair lands are turned to thirsty and 
inhospitable deserts, the hyperborean regions of Europe have 
learned to conquer, or rather compensate, the rigors of climate, 
and have attained to a material wealth and variety of product 
that, with all their natural advantages, the granaries of the 
ancient world can hardly be said to have enjoyed." 



PRIMER OF PRIMERS. 177 



XVIII. PRIMER OF PRIMERS. 

Forestry treats of the care and preservation of 
parts of the earth covered by trees, together with 
the best means of replanting such areas when 
deprived of their trees. 

When the germs are present, trees will grow 
naturally wherever suitable conditions of soil, heat, 
and moisture exist. 

The climatic conditions best suited for the 
growth of trees are also best suited for the growth 
of men. As density of population increases, the 
trees must be removed from large areas : 

1. For agricultural purposes. 

2. For the location of roads. 

3. For the wood or other products. 

The principal product of the forest is wood, 
which is required for fuel or charcoal, for building 
purposes generally, for fences, for telegraph-poles, 
for mining purposes, for railroad ties, or for bark 
for tanning. 

The object of forestry is to regulate the removal 
of the forest where necessary, and to point out the 



178 OUTLINES OF FORESTRY. 

best manner in which, the products of the forest 
may be harvested. 

Forestry does not endeavor to preserve intact 
the virgin forests of the earth. On the contrary, 
it teaches man how best to harvest the crops of 
wood, or, where necessary, to safely effect the 
entire removal of the forests. 

Among the different kinds of areas in agricul- 
tural districts suitable for tree-planting are, — 

1. Areas covered with poor or thin soils, where 
other crops will not thrive. 

2. Wet places, where other crops will not thrive. 

3. On the borders of rivers or streams generally. 

4. On mountain-slopes, hill-tops, or other eleva- 
tions. 

Forests should be maintained on mountain- 
slopes, because, — 

1. The rainfall is greatest on such slopes. 

2. Because the rivers are born in the mountains, 
and, when the forests are removed, the waters drain 
so rapidly from the surfaces of the slopes that 
dangerous floods occur, and much of the soil is 
rapidly carried away. 

3. Because the presence of the forest prevents 
the occurrence of disastrous droughts. 

4. Because the presence of the forest prevents 



PRIMER OF PRIMERS. 179 

sudden changes in the temperature of the air, and 
thus tends to increase the number and severity of 
hail-storms. 

5. Because the presence of the forest tends to 
prevent the occurrence of early frosts in the 
neighboring agricultural districts. 

6. Because the presence of the forest insures a 
greater uniformity in the relative quantity of 
moisture in the air at different seasons of the year. 

All life, whether animal or plant, has its begin- 
nings in a minute germ-cell containing a nucleus 
surrounded by a transparent substance called pro- 
toplasm. 

Although cases exist where plants appear with- 
out the apparent sowing of seed, yet, in all such 
cases, seeds or germs must have been present. 

The conditions necessary for plant-growth, named 
in the order of their importance, are : 

1. The germ or seed. 

2. The sunshine and the heatshine. 

3. The nourishment, or the food the plant re- 
quires for its growth. 

4. The cradle, or the soil in which the plant is 
born. 

When a particular species of plant life is to be 
maintained, the character of the soil is of the 



180 OUTLINES OF FORESTRY. 

greatest importance. But if the other conditions 
of heat, light, and nourishment exist, almost any 
soil will be found that will be the best fitted for 
some few of the great variety of plants. 

The germ or seed is in all cases derived from a 
plant similar to that which is produced when such 
seed grows and bears fruit. 

The soil forms the plant's cradle ; in it the plant 
spreads its roots, and obtains the water and min- 
eral ingredients required for growth. 

The moisture and carbonic acid taken from the 
air by a plant during its active growth form the 
principal part of the plant's structure ; the various 
mineral matters taken from the soil form but a 
comparatively small part of such structure. 

During active growth in the presence of sun- 
shine, plants take in or absorb carbonic acid from 
the air. Under the influence of sunlight, this car- 
bonic acid, together with its associated water, is 
eventually decomposed, the carbon and hydrogen 
being retained, and the oxygen thrown off into the 
air. 

The mineral matters in the soil must exist in 
such conditions as will permit of ready assimi- 
lation. 

Every section of country possesses a nationality 



PRIMER OF PRIMERS. 181 

in its plant growth, or produces a particular vari- 
ety of plants called its flora. 

The differences in the distribution of light, heat, 
and moisture in different parts of the earth cause 
corresponding differences in the flora of such parts. 

The flora of the equatorial regions consists of 
such plants as are best fitted to exist under the 
conditions of abundant heat, light, and moisture 
of these regions. 

In passing from the equator to the poles the 
differences in the distribution of heat and moist- 
ure cause corresponding differences in the variety 
and luxuriance of plant life. 

In passing from the base to the summit of a 
high tropical mountain similar differences in the 
variety and luxuriance of plant life are noticed, as 
in going from the equator to the poles. 

Seed-time and harvest seldom fail in nature, 
because the germs of vegetable life are generously 
scattered in all regions of the earth. 

The agencies provided by nature for widely 
scattering the seeds of plants are various. Some 
seeds are provided with delicate hair-like wings, 
which permit the wind readily to carry them great 
distances from the plants which produced them. 
Others are provided with hooks or bristles, which 

16 



182 OUTLINES OF FORESTRY. 

catch in the fur of animals or in the plumage of 
birds, and in this manner are often carried to 
distant regions. 

Some seeds, which are swallowed whole by 
birds or other animals, often pass out uninjured 
by the process of digestion at localities far distant 
from where they were produced. 

Civilized man either purposely or accidentally 
carries seeds from one locality to another. 

It sometimes happens that plants introduced 
into a particular section of country from a dis- 
tant land find the new soil and climate so favor- 
able to growth as to completely drive out and 
exterminate domestic species. 

The germs or seeds of plants often exhibit a 
remarkable tenacity of life under certain circum- 
stances. Grains of corn or wheat taken from 
Egyptian mummies have grown and borne fruit, 
notwithstanding their centuries of rest. 

In a densely-wooded section of country the 
ground is often so thickly covered by trees as to 
exclude all other forms of vegetable life. When, 
however, the removal of a few trees lets in the 
sunlight and heat, the seeds, which were possibly 
slumbering in the ground for centuries, at once 
spring into active life. 



PRIMER OF PRIMERS. 183 

When an artesian well is successfully dug in the 
Sahara Desert, the appearance of the water is 
almost invariably followed by the appearance of a 
flora that often contains species peculiar to such 
districts. 

Wherever the virgin soil of the prairies is up- 
turned, and thus exposed to the air, as by the 
wheels of the settlers' wagons or other causes, new 
species of plants appear. 

In the North Temperate Zone the burning of 
pine forests is almost invariably followed by the 
appearance of scrub-oak. 

This wide distribution of plant germs, together 
with their wonderful vitality, insure the natural 
growth of a vegetable covering in all regions of 
the earth where suitable conditions of soil, light, 
heat, and moisture exist. 

The character of the vegetation in any district 
depends more on peculiarities in the distribution 
of light, heat, and moisture in such districts than 
on the character of the soil. 

The peculiarities in the distribution of the rain- 
fall in any country determine to a great extent the 
character of the flora of such country. 

When the rainfall in any region is entirely ab- 
sent, no matter what the character of the soil may 



184 OUTLINES OF FORESTRY. 

be, or what the amount of light and heat such soil 
receives, vegetation will be entirely absent, and 
the region will become a desert. 

Where rain falls during one part of the year, 
and the rest of the year is dry, steppe regions 
occur. Such regions are covered by vegetation 
during the wet season, but resemble deserts during 
the dry season. 

Meadows and prairies occur where the rainfall 
is well distributed throughout the year, and the 
quantity is not very great. 

Forests occur where there is an abundant rain- 
fall well distributed throughout the year. 

Forests cannot exist in any part of the North 
Temperate Zone where the rainfall is absent for 
a considerable length of time, because the trees 
would die during the dry season, and there would 
be no germs for a new crop of trees to start grow- 
ing from on the appearance of the rainy season. 

In certain parts of the tropics forests may exist 
despite long periods of drought, because in such 
regions the growth of the trees is either considera- 
bly retarded, or the trees obtain their liquid nour- 
ishment from copious dews or directly from the 
vapor of the air. 

A certain depth and character of soil are neces- 



PRIMER OF PRIMERS. 185 

sary for the growth of trees. Such a soil was 
formed by the gradual disintegration of hard 
rocks, and by the growth and subsequent decay 
of thousands of generations of plants. 

Forests are generally found on the slopes of 
mountains, where the rainfall is considerable and 
well distributed throughout the year. The moun- 
tains are, therefore, the natural home of the forest. 

Forests are found especially on that coast of an 
island or continent which is exposed to the preva- 
lent wind, because there the rainfall is considera- 
ble and no extended time occurs when the rain is 
absent. 

Soil was originally formed by the gradual disin- 
tegration of the crystalline rocks that were pro- 
duced by the cooling of the earth's crust. 

Disintegration of rocks is effected by various 
causes, mainly, however, by the action, in some 
way or another, of water. 

Sometimes the soil is found resting on the sur- 
face of the rock from which it was derived by 
disintegration. In such cases its general charac- 
ter can be directly traced to the composition of the 
underlying rocks by the gradual change which can 
be observed from the loose, porous soil on top, to 
the hard, untouched, virgin rock below. 

16* 



186 OUTLINES OF FORESTRY. 

Soils maybe divided into gravelly, sandy, clayey, 
calcareous, and peaty. 

The agencies by which the hard crystalline 
rocks may be broken up or disintegrated to form 
soil are, — 

1. The expansion produced during the sprout- 
ing or growing of vegetation. 

2. The alternate contractions and expansions 
that attend the freezing or thawing of the water 
that sinks into the rocks. 

3. The cutting or eroding power of running- 
water charged with suspended mineral matters. 

4. The eroding or cutting power of glaciers. 

5. The solvent power of water containing such 
gases as oxygen or carbonic acid. 

A plant, during its vigorous growth, by the ex- 
pansion of its roots, may break or rend a rock, 
and thus aid in its disintegration. 

The alternate expansions and contractions that 
attend the thawing or freezing of the water which 
sinks into a rock gradually break the rock into 
fragments, and thus aids in the formation of soil. 

During the gradual movements of glaciers down 
the mountain valleys, the fragments of hard rocks 
lodged in the ice cut or grind the rocks which 
form the sides of the valleys through which the 



PRIMER OF PRIMERS. 187 

glaciers move, and thus aid in the formation of 
soil. 

When water contains dissolved in it oxygen or 
carbonic acid gas, it may gradually dissolve some 
of the less insoluble ingredients of the hardest 
rocks, and thus cause them to become permeable. 

Clayey soils are derived from the disintegration 
of feldspathic rocks. 

Calcareous soils are derived from the disintegra- 
tion of limestones. 

Some soils possess the valuable property of ab- 
sorbing moisture directly from the vapor in the 
air. Soils containing a large quantity of vegetable 
humus possess this property in a more marked 
degree than any others. Clayey soils also possess 
it to a marked extent. 

The ability of soils to absorb the sun's heat will 
vary with their color. Dark-colored soils absorb 
the heat much better than light-colored soils. 

The plants that are found growing naturally in 
any locality are those which are best fitted to grow 
in such locality. They will continue to grow 
naturally only so long as these favorable con- 
ditions are maintained. 

Forests require for their continued existence a 
certain character of soil, so that, although even all 



188 OUTLINES OF FORESTRY. 

the climatic conditions requisite for their growth 
exist, they cannot appear until such soil is provided. 

Like other forms of creation, the forest is forced 
to maintain a continual struggle for existence. 

Its enemies may be divided into two classes, — 
namely, animate and inanimate. 

The principal animate enemies of the forest are 
plants, animals, and man. 

The principal inanimate enemies of the forest 
are fire, winds, floods, and avalanches. 

The destruction of the forest by fire is generally 
complete. Though in some cases a small fire may, 
by destroying the less hardy forms of plant life, 
increase the growth of certain trees, such, for 
example, as the pitch-pine, yet, in general, exten- 
sive forest fires generally so completely remove the 
forests, that it is often impossible to re-establish 
them. 

Severe forest fires generally occur during the 
dry season of the year. The rain which subse- 
quently falls finds the ground unprotected by any 
vegetable covering, and, rapidly draining off the 
surface, carries away much soil. 

The principal causes of forest fires are the camp- 
fire, the burning of brush, the locomotive spark, 
the lightning-bolt, and at times, perhaps, the heat- 



PRIMER OF PRIMERS. 189 

ing power of the sun's rays concentrated by len- 
ticular, resinous, or gummy nodules. 

"When its velocity is great, the wind sometimes 
sweeps away the trees from extended areas. This 
action of the wind is limited mainly to the edges 
of the forest or to openings made in them by any 
cause. 

By overflowing their banks, rivers sometimes 
undermine and carry away thousands of acres of 
forest trees. The trees accumulate in the bed 
of rivers and form masses called rafts. 

An avalanche sweeping down the slope of a 
mountain often completely removes the forest. A 
plot of forest land, properly placed, will often 
check the movements of avalanches. 

The animate enemies of the forest often produce 
their greatest destruction by the aid of the inani- 
mate enemies. Thus, man destroys forests by fire ; 
the beaver, by floods. 

Various parasitic plants may grow on, and 
thus cause the death of, even the most vigorous 
trees. 

Some forms of fungus-growth cause considera- 
ble damage to the trees on which they grow. 

The animal enemies of the forest vary in size 
from minute insects to animals of large size. 



190 OUTLINES OF FORESTRY. 

The ravages of the animal kingdom are most 
marked on the borders of the forest. In the 
deeper recesses, the vegetable kingdom holds 
almost undisputed sway, excluding the animal 
forms by the density of its growth. 

Domestic animals, when allowed to range freely 
through the forest, may cause considerable damage, 
by destroying the foliage, or by gnawing the bark 
of trees. 

Among wild animals, rodents are the most de- 
structive by gnawing the bark, and often by com- 
pletely girdling the trees. 

Rabbits, mice, and beavers are among the ro- 
dents that cause the greatest damage to the 
forests. 

Beavers destroy forests not only by actually 
cutting down trees, but also by building dams 
which cause the overflowing of the adjacent coun- 
try, which thus destroys the timber growing 
thereon. 

Goats and other animals that live largely on the 
bark of trees often work great destruction to the 
forests. 

Insects cause damage to the forests, either by 
feeding on the parts of the tree necessary for re- 
production or growth, or by making galleries or 



PRIMER OF PRIMERS. 191 

tunnellings through the wood. Many insects, 
while in the larva state, cause great damage to 
trees by boring or eating the wood. 

Various caterpillars often cause so great a de- 
struction to the piue-trees as to completely destroy 
extensive pine forests. 

The greatest enemy of the forest is man. As 
lord of the forest he is entitled to its products, and 
if he exercises judgment he can safely harvest his 
forest crops. 

The removal of the forests from any considera- 
ble section of country is almost invariably attended 
by some or all of the following results, — namely : 

1. An increase in the frequency and severity of 
the inundations of the rivers flowing in or through 
such districts. 

2. An increase in the number and severity of 
droughts in such districts. 

3. A rapid loss of the soil of the area from 
which the trees have been removed. 

4. A marked disturbance in the lower courses 
of the rivers which rise in, or flow through, such 
districts. 

5. An increase in the number and severity of 
hail-storms. 

When the forests are removed from any area, 



192 OUTLINES OF FORESTRY. 

the rain which falls on such area, instead of 
slowly draining into the river channel during a 
comparatively long time, drains rapidly into it 
and causes disastrous floods. The reservoirs of 
the springs in such districts thus failing to receive 
their proper supply of water, are apt to dry up 
shortly after the beginning of the drought. 

The rapid drainage of the areas from which the 
forests were removed causes a loss of its surface- 
soil. 

The soil thus lost to the highlands is deposited 
in the lower courses of the rivers, in the shape of 
mud-flats, or sand-bars, which injuriously affect 
navigation. 

"When soil, rich in vegetable humus, deposited 
on the lowlands near the mouths of rivers, is ex- 
posed to the sun's heat, is apt to cause miasmatic 
or other diseases. 

The ground left bare by the destruction of the 
forest permits it to both take in and part with its 
heat rapidly, and thus to permit the air over it 
to rapidly grow hot in summer and cold in winter. 

Forests should be maintained in some parts of 
all regions where trees can grow. The best places 
for such purposes are to be found on the slopes of 
mountains. 



PRIMER OF PRIMERS. 193 

From every water surface of the earth vapor is 
almost constantly passing into the atmosphere. 
This vapor diffuses through the air over such 
water surfaces, and is carried by the winds to 
different regions of the earth. 

The heat which turns water into vapor disap- 
pears, or becomes what is commonly called latent 
heat. When such vapor is sufficiently chilled and 
falls as rain, snow, or other form of precipitation, 
the latent heat becomes sensible and warms the 
surrounding air. 

The rapidity with which water evaporates or 
passes into the air as vapor varies with the follow- 
ing circumstances : 

1. The extent of the surface exposed. 

2. The temperature of the air. 

3. The quantity of vapor already in the air. 

4. The pressure. 

The vapor which passes into the air exerts a 
considerable influence in moderating the extreme 
temperatures that would otherwise exist in the 
equatorial and polar regions of the earth, in the 
following ways, viz. : 

1. By effecting an interchange between the 
excessive heat of the equatorial regions and the 
excessive cold of the polar regions. 

in 17 



194 OUTLINES OF FORESTRY. 

2. By acting as a screen which both prevents the 
earth's surface from being too rapidly heated on 
exposure to the sun's rays, or too rapidly cooled 
when deprived of such rays. 

Since air can hold more vapor when hot than 
when cold, if the temperature of a mass of warm 
moist air is sufficiently cooled, the moisture it can 
no longer hold as vapor appears as rain or as some 
other form of precipitation. 

The lowering of temperature required to pro- 
duce rain is obtained : 

1. By warm moist air blowing along the earth's 
surface towards colder regions. 

2. By warm moist air rising directly from the 
earth's surface into the higher and colder regions 
of the atmosphere. 

Rain is generally caused by warm moist air 
blowing towards the polar regions of the earth. 
Cold dry air blowing towards the equatorial re- 
gions has its capacity for moisture increased, and 
tends rather to cause droughts than rain. 

In tropical regions, a wind that has crossed an 
ocean, and has thereby become saturated with 
moisture, may bring rain on reaching the coast of 
a continent or island, in no matter from what 
direction it comes. 



PRIMER OF PRIMERS. 195 

More rain falls in the equatorial regions than 
elsewhere ; more falls in the temperate than in the 
polar regions. More rain falls on the coasts of 
continents than in the interior. 

Where the temperature is sufficiently high, as in 
the equatorial regions, rain may be caused by the 
chilling produced by ascending currents. 

Mountains cause a heavy rainfall on account of 
the air being chilled when forced to ascend their 
cold slopes. 

Nearly all the great rivers of the world rise in 
mountainous districts. 

The rain that falls on the earth either runs di- 
rectly off the surface or sinks slowly into the 
ground. The part that runs directly off the sur- 
face collects in streams that discharge directly into 
the rivers. The part that sinks into the ground 
collects in underground basins, from which it 
slowly emerges as springs. 

When the mountains are covered by forests, the 
rain which falls on their slopes, for the greater 
part, drains slowly into the ground. When the 
mountains are denuded of their forests most of 
the rain drains rapidly off the surface. The de- 
struction of the forests on mountain-slopes is, 
therefore, apt to cause floods. 



196 OUTLINES OF FORESTRY. 

The running of the water from a higher to a 
lower level is called drainage. 

There are two kinds of drainage : 

1. Surface drainage, where the water runs di- 
rectly off the surface into the rivers. 

2. Underground drainage, where it first sinks 
into the ground and afterwards discharges as 
springs into the rivers. 

Underground drainage takes place slowly. Sur- 
face drainage takes place rapidly. 

The direction in which rivers flow depends on 
the direction in which the land slopes. 

The main stream, with all its tributaries and 
braDches, is called the river system. The land 
which drains into a river system is called the river 
basin. The size of the river depends on the ratio 
between the quantity of the rainfall and the size 
of the river's basin. 

When a river basin is covered with a loose, por- 
ous soil, such as it will have when covered with 
almost any form of vegetation, the rain sinks 
slowly into the earth and the river seldom over- 
flows its banks. 

When the area is such that most of the water 
runs directly off the surface, as will generally be 
the case when deprived of its vegetable covering, 



PRIMER OF PRIMERS. 197 

the rivers receiving such drainage are apt to over- 
flow their banks during the wet season. 

Any disturbance in the natural drainage of a 
country may cause damage from the too rapid 
drainage of its surface : 

1. By insuring too much water in its rivers 
during inundations. 

2. By insuring too little water in its rivers 
during drought. 

The preservation of forests on mountain-slopes, 
where the drainage is more rapid than elsewhere, 
insures a proper drainage of its surface, and con- 
sequently the proper flow of its rivers. 

The condition of the air of a country as regards 
its heat or cold moisture or dryness, healthfulness 
or unheal thfulness, is called its climate. 

The atmosphere receives its heat from the sun : 

1. Directly, by absorption. 

2. Indirectly, from the heated earth. 

The atmosphere receives its heat indirectly from 
the heated earth : 

(a) By contact with the heated earth. 

(b) By radiation from the heated earth. 

(c) By reflection from the heated earth. 

All parts of the earth in the same latitude do 
not possess the same temperature, because the 

17* 



198 OUTLINES OF FORESTRY. 

surface is higher in some places than it is in 
others, in some places is covered with vegetation 
and in others is bare, or is exposed to cold or 
currents of wind or water in some places and to 
warm currents in others. 

Differences in the elevation of the land cause 
differences in the temperature of the air. An 
elevation of three hundred and fifty feet will cause 
the same lowering of temperature as a difference 
of one degree of latitude, — viz., of 1° Fah. 

The same changes of temperature are observed 
in passing from the base to the summit of a high 
tropical mountain as in passing along the earth's 
surface from the equator to the poles. 

Portions of the earth's surface covered by water 
heat or cool slowly; consequently, the air over 
such portions does not change its temperature 
rapidly, or, in other words, such portions of the 
earth possess an equable climate. Portions of 
the earth covered by land heat and cool rapidly ; 
consequently, the air over such portions changes 
its temperature rapidly, or, in other words, such 
portions possess a variable climate. 

A surface covered with vegetation — such, for 
example, as a forest — does not change its tempera- 
ture as rapidly as it* would if it were bare. Forests, 



PRIMER OF PRIMERS. 199 

therefore, tend to prevent sudden changes in the 
climate. 

A bare, uncovered area, such as a desert, is sub- 
ject to sudden changes in its climate. 

The climate produced by an extended land area 
is called a continental climate; that produced by 
an extended water area, an oceanic climate. A 
continental climate is characterized by great and 
sudden changes of temperature; an oceanic 
climate, by a comparatively uniform temperature. 
The forests tend to produce a climate characterized 
by a comparatively uniform temperature. In this 
respect, therefore, the forest climate is like the 
oceanic climate. 

The sun does not heat an area covered by forests 
either as intensely or as rapidly as a bare area, 
because : 

1. The heat is spread over the greatly-extended 
surfaces formed by the trees of the forest and its 
underbrush. 

2. The vegetable covering acts as a screen to 
protect the ground from the direct action of the 
sun's rays. 

3. The air over the forest is moister than that 
over the fields, and this moist air acts either as a 
screen to protect it from th*e heat of the sun, 



200 OUTLINES OF FORESTRY. 

or to prevent the loss of its own heat by radia- 
tion. 

Therefore, an area of ground covered with for- 
ests is subjected to smaller changes of temperature 
than a bare, uncovered area. 

The climate of the forest is more equable than 
that of the open fields, because the forest takes 
in and parts with its heat more slowly than the 
fields. 

A layer of snow tends to preserve the tempera- 
ture of the ground on which it falls. If snow 
falls on unfrozen ground, the ground will probably 
remain unfrozen throughout the year until the 
snow melts ; and, when the melting occurs, the 
water will drain slowly into the earth. If, how- 
ever, the snow falls after the ground is frozen, the 
ground will probably remain frozen until the snow 
melts, when the water will drain rapidly off the 
surface. 

The presence of the forest tends to keep the 
ground unfrozen until protected by a layer of 
snow, and in this way, when the snow melts, the 
water sinks quietly into the ground, and disastrous 
floods are thus avoided. 

The forest, by keeping the air over it moister than 
that over the fields, increases the ability of the air 



PRIMER OF PRIMERS. 201 

to take in heat, either directly from the sun, or in- 
directly from the heated earth. 

Forests prevent sudden changes of temperature 
throughout the year. In early autumn they de- 
crease the frequency of destructive frosts by pre- 
venting the temperature of the air from rapidly 
falling. 

The presence of forests over extended areas pre- 
vents the occurrence of sudden changes of tem- 
perature. 

1. By permitting such areas to more thoroughly 
absorb the sun's heat, on account of the greater 
surfaces they possess. 

2. By keeping the air over the forests moister 
than over the open fields, thus enabling it more 
readily to absorb the sun's heat. 

3. By acting as a screen to the lands lying to the 
leeward of cold winter winds. 

4. By preventing the frosts from penetrating 
great distances into the ground, and, therefore, in- 
creasing the chance of winter snows falling on 
unfrozen ground. 

The atmosphere is composed of a mixture of 
about seventy-seven per cent, by weight of nitro- 
gen and twenty-three per cent, of oxygen. It also 
contains a nearly constant quantity of carbonic 



202 OUTLINES OF FORESTRY. 

acid gas and a variable quantity of the vapor of 
water. 

The oxygen of the air is necessary for animal 
life. The carbonic acid gas is necessary for plant 
life. The moisture is necessary for both animal 
and plant life. 

Animals take in oxygen and give out carbonic 
acid gas. During growth, when exposed to sun- 
shine, plants take in carbonic acid gas and give out 
oxygen. 

The presence of both animal and plant life, 
therefore, is necessary to keep the composition of 
the atmosphere the same. 

In the geological past the earth's atmosphere 
was vaster than at present. It contained more 
oxygen and more carbonic acid than it does now. 
Much of the oxygen, which then existed in a free 
state in the air, is now combined with various ma- 
terials that form the earth's crust. 

The excess of carbonic acid which existed in the 
earth's atmosphere during the geological past was 
removed from it mainly by the plants of the car- 
boniferous period, and now exists in the earth as 
beds of coal. 

In order to avoid any disturbance in the balance 
between plant and animal life of the earth, forests, 



PRIMER OF PRIMERS. 203 

which represent the largest forms of plant life, 
should be preserved. 

Hail occurs when considerable differences of 
temperature exist between neighboring masses of 
very moist air. 

The destruction of the forest, by readily per- 
mitting such differences of temperature to occur, 
tends to increase the number and severity of hail- 
storms. 

A hail-storm is generally preceded by the ap- 
pearance of several layers of dark grayish clouds, 
and a violent movement is often seen to occur be- 
tween them, that is probably of a whirling char- 
acter. 

Hail-storms are almost invariably attended by 
marked disturbances in the electrical equilibrium 
of the atmosphere. 

A hailstone is formed of alternate layers of ice 
and snow. Various explanations have been offered 
to account for the peculiar structure. Yolta as- 
cribed it to the alternate attractions and repulsions 
occurring between neighboring snow- and rain- 
clouds, when charged with opposite kinds of elec- 
tricity. 

In France, where Volta's theories were formerly 
received, lightning-rods were fruitlessly erected on 



204 OUTLINES OF FORESTRY. 

the fields in order to protect them from the ravages 
of the hail. 

The peculiar structure of the hailstone has also 
been ascribed to a whirling motion of the air be- 
tween snow- and rain-clouds around a horizontal 
axis, whereby particles of snow are carried alter- 
nately into the rain- and snow-clouds, and thus 
receive their alternate coatings. 

Another theory accounts for the alternate coat- 
ings of ice and snow by the exposure of moisture 
to the different temperatures occurring in denser 
and rarer portions of space around which the wind 
is whirling. 

By reforestation is meant the replanting of trees 
in any locality from which they have been removed 
either accidentally or purposely. 

Provided the removal of the forest has not been 
attended by too great a loss of soil, the same kind 
of trees may be successfully replanted. 

There are two methods by means of which 
reforestation may be effected. 

1. Sowing or Seeding. 

2. Tree Planting. 

Seeding can be profitably followed in the tem- 
perate latitudes where the growth of the tree is 
comparatively certain. In higher latitudes the 



PRIMER OF PRIMERS. 205 

planting of the tree is, perhaps, preferable, since 
the germination and continued growth of seeds 
are by no means certain. 

"Where the destruction of the forest has been 
caused by an avalanche, the removal of the soil, 
in some cases, is so complete that trees cannot be 
successfully replanted. 

In some of the western parts of the United 
States it is now recognized, from actual experience, 
that when trees are planted in plots around the 
farm-lands, the protection thus afforded the rest 
of the farm-land, against the winds, is of greater 
money- value than the rent of the ground occupied 
by such trees. 

The following locations are especially adapted to 
tree planting : 

1. "Wet lands. 

2. Lands covered with a thin or poor soil. 

3. Along the margins of rivers where the land 
is not required for roads or other public pur- 
poses. 

4. On the side of mountain-slopes where the soil 
is of the proper character, or subject to destructive 
avalanches. 

An exact balance must be preserved between 
the five great geographical forms, — namely, the 

18 



206 OUTLINES OF FORESTRY. 

land, the water, the air, the plants and animals, in 
order that the complex organization of nature may 
be properly maintained in operation. 

The energy which is the cause of nearly all 
natural phenomena of the earth is received directly 
from the sun. 

One part of the sun's heat stirs the air and 
water in vast movements between the equator and 
the poles, and thus effects an interchange between 
the too great heat of the equatorial regions and 
the too feeble heat of the polar regions. Another 
part of the solar energy is directly expended in 
producing one or another of the myriad forms of 
plant or animal life. 

If the land, the water, or the air receives more 
than its share of solar energy, a disturbance in 
the balance of nature is effected, which produces 
marked effects in the life of the earth. 

The total water area of the earth bears a pro- 
portion to its total land area very nearly as 25 is to 
9, or as 2J is to 1. 

The earth receives its greatest heat from the 
sun at those parts of its surface where it has its 
greatest water areas, only a comparatively small 
part of the land being found in the equatorial re- 
gions. There are produced, however, vast currents 



PRIMER OF PRIMERS. 207 

in the atmosphere and in the ocean, which effect 
an interchange between the heat of the equator 
and the cold of the poles. 

Any change in the distribution of the land and 
water areas of the earth, either as regards their 
relative amount, or as regards their distribution, 
would seriously affect the life of the earth. 

If the greatest proportion of land existed at the 
equator, such changes would be produced in the 
earth's climate as to sweep its present life out of 
existence. 

Any change in the elevation of the present land 
areas would produce a marked change in the 
earth's climate. It was probably an increase in 
the elevation of the polar lands that caused the 
severe cold of the glacial epoch, when so much 
of the northern continents were covered with 
ice. 

In order to preserve the present relative propor- 
tions of oxygen and carbonic acid in the atmos- 
phere, the present animal and plant life of the 
earth must be preserved. 

Animals are absolutely dependent on plants for 
their existence. The plants can take their food 
directly from the air and the soil. Animals re- 
quire their food to be prepared for them by the 



208 OUTLINES OF FORESTRY. 

plants on which they live. The death of the plant 
life of the earth would, therefore, he followed by 
the death of all its animals. 

Many animals multiply so rapidly that, unless 
they were removed from the earth by furnishing 
food for other animals, a marked disturbance would 
be effected in the balance of nature. 



APPENDIX. 



LISTS OF TKEES SUITABLE FOE REPLANTING IN 
DIFFERENT PORTIONS OF THE UNITED STATES. 

In order to extend the scope of the Outlines of For- 
estry, and to render it of greater practical value, the follow- 
ing circular letter was sent to different well-known authorities 
in forestry, inquiring as to lists of trees suitable for replanting 
in different sections of the United States. 

Circular Letter. 

Philadelphia, January 23, 1892. 

1809 Spring Garden Street. 



Prof. 



Dear Sir, — I am about publishing a little work on For- 
estry, and am desirous of obtaining a list of trees suitable for 

planting for reforestation in such parts of. 

and the adjoining States as have been denuded of forests, 
or are capable of sustaining forest trees. 

In the event of your being able to spare the time necessary 
o 18* 209 



210 APPENDIX. 

to send me a list of such trees, I would, of course, make foil 
acknowledgment in the book of your contribution. 

If your time is too folly occupied to send me the infor- 
mation requested, can you inform me where I can obtain the 
same? 

Asking your pardon for thus trespassing on your valuable 

time, I am, 

Very respectfully, yours, 

Edwin J. Houston. 

The letters received in reply to the foregoing, together with 
the lists of trees suitable for purposes of reforestation, are 
hereunto appended. 

From Thomas Meehan, Editor of Meehan's Monthly, German,' 

town, Philadelphia. 

Meehan's Monthly, 
Germantown, Phil ad a., January 30, 1892. 

Prop. Edwin J. Houston, 

1809 Spring Garden Street, Philadelphia. 
Dear Sir, — I have marked in the catalogue sent to-day 
the names of such trees as are most desirable for planting on 
the Northeastern Seaboard of the United States. A few are 
rare, but will soon become common ; others are not likely to 
become common for some years. In some cases the trees 
marked would have but limited usefulness, but all are of 
value in some respect or another. 

When getting into the States along the seaboard of the 
Virginia line, many of those named would be ineligible. 
Very truly yours, 

Thomas Meehan. 



APPENDIX. 211 

DECIDUOUS TREES. 
MAPLES. 

Acer campestre, or European Cork Maple. 
" palatanoides, or Norway Maple. 
" pseudo-platanus, or European Sycamore Maple. 

HORSE-CHESTNUT. 

jEsculus glabra, or American Horse-Chestnut. 

" hippocastanum, or European Horse-Chestnut. 

AILANTUS. 

Aila?itus glandulosa. 

BIRCH. 

Betula alba, or European White Birch. 

HICKORY. 

Carya alba, or Shell-bark Hickory. 
" amara, or Bitternut Hickory. 
" microcarpa, or Small-Fruited Hickory. 
" sulcata, or Large-Fruited Hickory. 
" tomentosa, or White Hickory. 

SWEET CHESTNUT. 

Castanea Americana, or American Chestnut. 

HOLLY. 

Hex opaca, or American Holly. 

JUNIPER, CEDARS. 

Juniperus Virginiana, or Eed Cedar. 

FIR. 

Picea balsamea, or Balsam Fir. 

PINE. 

Pinus Austriaca, or Australian Pine. 
" Banksiana. 
" densiflora, or Japan Pine. 
" Laricio, or Corsican Pine. 



212 APPENDIX. 

Pinus Massoniana. 
" pungens. 

" resinosa, or Eed Pine. 
" rigida, or Pitch Pine. 
" mitis, or Yellow Pine. 
" strobus, or White Pine. 

JAPAN CYPRESS. 

JRetinispora obtusa. 

ARBOR-VIT^E. 

Thuja occidentalis, or American Arbor Vitse. 
LOCUST, ACACIA. 

Eobinia pseudacacia, or Yellow Locust. 

MAIDEN-HAIR TREE. GINGKO. 

Salisburia adiantifolia. 

WILLOW. 

Salix alba, or White Willow. 

" Babylonica, or Weeping Willow. 

" japoniea, or Japan Willow. 

" pentandra, or Laurel-leaved Willow. 

" Mussettiana. 

" vitellina, or Golden-Bark Willow. 

ELMS. 

Ulmus Americana, American Elm. 
" campestris, or English Elm. 
" fulva, or Slippery Elm. 
" racemosa, or American Cork Elm. 

EVERGREENS. 
SPRUCE. 

Abies alba, or White Spruce. 
" Canadensis, or Hemlock. 



APPENDIX. 213 



Abies Douglasii, or Douglas Spruce. 
" excelsa, or Norway Spruce. 
" pungens, or Colorado Blue Spruce. 
LARCH. 

Larix Europcea, or European Larch. 

SWEET GUM. 

Liquidambar styraciflua. 

SOPHORA. 

Sophora Japonica. 

DECIDUOUS CYPRESS. 

Taxodium distichum. 

LINDEN. 

Tilia Americana, or American Linden. 
" Europcea, or European Linden. 

POPLAR. 

Populus alba, or Silver Poplar. 

" balsamifera, or Balsam Poplar. 
" fastigiata, or Lombardy Poplar. 
" grandidentata. 
" monilifera, or Carolina Poplar. 



OAK. 



lercus alba, or White Oak. 

" bicolor, or Swamp White Oak. 

" cerris, or Turkey Oak. 

" Goccinea, or Scarlet Oak. 

" dentata (Daimio), or Japan Oak. 

" falcata, or Spanish Oak. 

" imbricaria, or Laurel Oak. 

" macrocarpa, or Mossy Cup. 

" nigra, or Black Jack Oak. 

" obtusiloba } or Post Oak. 



214 APPENDIX. 

Quercus palustriis, or Pin Oak. 
phellos, or Willow Oak. 
prinus, or Eock Chestnut Oak. 
robur, or English. Oak. 
rubra, or Eed Oak. 
tinctoria, or Black Oak. 

MULBERRY. 

Morus alba, or White Mulberry. 

" rubra, or American Eed Mulberry. 
BOX ELDER. 

Negundofraxinctfolium, or Ash-leaved Maple. 
SOUR GUM. 

Nyssa muttiflora. 

IRONWOOD. 

Ostrya Virginica. 

EMPRESS-TREE. 

Paulownia imperialis. 

BUCKEYE. 

Paviafiava, or Yellow Buckeye. 

CHINESE CORK-TREE. 

Phellodendron amurense. 

PLANERA. 

Planera cuspidata. 

BUTTONWOOD, PLANE. 

Plantanus occidentals, or American Plane. 
" orientalis, or Oriental Plane. 
HONEY LOCUST. 

Gleditschia triacanthos, or Honey Locust. 

KENTUCKY COFFEE. 

Gymnocladus Canadensis. 



APPENDIX. 215 

HOVENIA. 

Hovenia dulcis. 

IDESIA. 

Idesia polycarpa. 

WALNUT. 

Juglans cinerea, or Butternut. 

" regia, or English Walnut, or Madeira Nut, — south 
of Philadelphia. 
TULIP-TREE. 

IAriodendron tulipifera, or Common Tulip-Tree, or Tulip 
Poplar. 
OSAGE ORANGE. 
Madura aurantiaca. 

MAGNOLIA. 

Magnolia acuminata, or Cucumber-Tree. 
" macrophylla. 
" tripetala, or Umbrella-Tree. 

CATALPA. 

Catalpa bignonioides, or Catalpa. 
" speciosa, or Western Catalpa. 

NETTLE-TREE. 

Celtis occidentalis, or Nettle-Tree. 

CHERRY. 

Cerasus avium alba plena, Double-flowering Cherry. 
" Pennsylvania, or Wild Bed- Cherry. 
" ranunculceflora. 

DOGWOOD. 

Cornus Florida, or White or Large-flowering Dogwood. 

PERSIMMON. 

Diospyros Virginiana, or American Persimmon. 



216 APPENDIX. 

BEECH. 

Fagus Americana, or American Beech. 
" sylvatica, or European Beech. 

ASH. 

Fraxinus Americana, or White Ash. 
" excelsior, or European Ash. 
" quadrangulata, or Blue Ash. 
" sambucifolia, or Black Ash. 
" viridis, or Green Ash. 

KATSURA. 

Cercidiphyllum japonicum. 



From B. S. Hoxie, Secretary of the Wisconsin State Horticultural 
Society. 

Wisconsin State Horticultural Society, 

Evansville, Wisconsin, January 26, 1892. 

Edwin J. Houston, Philadelphia, Pa. 

Dear Sir, — Yours of the 28th at hand. I mailed to your 
address our last volume, No. 2, I think. The list of trees 
found on page 9, which we recommend for general planting, 
will be found applicable to nearly all parts of our State. 

The pine regions of Wisconsin are the parts that are now 
being deforested, and no special effort is being made to re- 
forest these areas. Oak, ash, maple, birch, elm, pine, and 
spruce will grow on most of this land. 

We have several townships bordering on Lake Superior in 
Bayfield County, which some ten years ago were set apart 
as a State Park. Last winter a bill was introduced to bring 
this reservation into the market, — i.e., to sell the timber, but it 



APPENDIX. 217 

failed to pass, and if my pen and the press can prevent such 
a bill, it will never pass. If I can be of any further assistance 
to you, please write me. 
I shall be glad to see your book when published. 

Respectfully, 

B. S. Hoxie. 

TREES AND SHRUBS RECOMMENDED. 

Trees and shrubs recommended in the " Annual Report of 
the Wisconsin State Horticultural Society." * 

EVERGREENS. 
For general planting in the order named : 

White Pine. 

Norway Spruce. 

White Spruce. 

Arbor Vitse. 

Balsam Fir. 

Austrian Pine. 

Scotch Pine. 
For ornamental planting in the order named : 

Hemlock. 

Red Cedar. 

Siberian Arbor Vitse. 

Dwarf Pine. 

Red or Norway Pine. 

* Annual Report of the "Wisconsin State Horticultural Society, em- 
bracing papers read and discussions thereon at the semi-annual meeting 
held in Black River Falls, June 25, 27, 1890 ; also at Madison, June 
2-6, 1891. Vol. xxi. p. 9. 

x 19 



218 APPENDIX. 

DECIDUOUS TREES. 
For Timber. 
White Ash. 
Black Walnut. 
Hickory. 
Black Cherry. 
Butternut. 
White Oak. 
European Larch. 
American Larch. 

Street Shade- Trees. 
White Elm. 
Hard Maple. 
Basswood or Linden. 
Ashleaf Maple {Acer negundo.) 
Norway Maple. 
Hackberry. 

For Lawn Planting. 

Weeping Cut-leaved Birch, 
American Mountain Ash. 
Green Ash. 
Horse-Chestnut. 
European Mountain Ash. 
Wisconsin Weeping Willow. 
Oak-leaved Mountain Ash. 
White Birch. 

Weeping Golden-barked Ash. 
Weeping Mountain Ash. 
Weeping Poplar. 



APPENDIX. 219 

From Charles Mohr, Agent for the Forestry Division of the 
United States Department of Agriculture, Mobile, Alabama. 

U. S. Department of Agriculture, 

Mobile, Alabama, January 31, 1892. 

Prof. Edwin J. Houston, Philadelphia, Pa. 

Dear Sir, — Your letter of the 23d has been received. 
According to your request, I send you enclosed a list of timber 
trees, which might be regarded as adapted for the reforestation 
of denuded areas in the Gulf States east of the Mississippi 
Kiver. 

In the selection of the trees, I had to be guided solely by 
my observations made in the different sections of the regions 
named, and had to confine myself entirely to native species, 
no information being on hand in regard to trees from other 
sections of the United States, or exotics. 

To shorten matters, I refer you for information about the 
habits of the species named in the list, to the preliminary of 
important forest trees in the United States, in Mr. Fernow's 
" Eeport to the Commissioners of Agriculture" (Forestry Di- 
vision) for the year 1886, where, also, notes on the economic 
uses of each will be found. The numbers in my list refer to 
the same species mentioned in the above report. 
I remain truly yours, 

Charles Mohr. 

White Cedar, Ghamcecyparis sphceroidea. 
Bed Cedar, Juniperus Virginiana. 
Bald Cypress, Taxodium distichum. 
Long-leaved Pine, Pinus palustris. 
Loblolly Pine, Pinus tozda. 



220 APPENDIX. 

Cuban Pine, Pinus Cubensis. 

Short-leaved Pine, Pinus mitis. 

White Oak, Quercus alba. 

Cow Oak, " Michauxii. Eich, alluvial soil. 

Chestnut Oak, " prinus. 

Live Oak, " virens. Lower districts. 

Eed Oak, " rubra. 

Black Oak, " tinctoria. Gravelly uplands. 

Spanish Oak, " falcata. Throughout on lighter soils. 

Water Oak, " aquatica. Of value for fuel only. 

Willow Oak, " Phellos. Eapid growth on wet or dry 
light soil. Timber more valuable. 

Beech, Fagus ferruginea. 

Chestnut, Castanea vulgaris, var. American. In dry, some- 
what silicious soils throughout. 

Shell-bark Hickory, Carya alba. Upper and central districts. 

Mocker Nut, Carya tomentosa. 

Pecan, Hickoria Pecan {Carya olivmformis). Valuable for its 
fruit. 

Wild Cherry, Prunus serotina. 

Sweet Gum, Liquidambar Styraciflua. 

Black Locust. 

Honey Locust. 

Eed Mulberry, Morus rubra. Shade-loving. 

Magnolia, Magnolia grandiflora. 

Cucumber Tree, Magnolia acuminata. In well-drained, deep, 
and lighter loamy soil, through the State. Shade-loving. 

Tulip- Tree, Liriodendron tulipifera. 

Osage Orange, Madura aurantiaca. 

White Ash, Fraxinus Americana. Upper district. 



APPENDIX. 221 

Green Ash, Fraodnus viridis. 

Eed Maple, Acer rubrum. 

Silver Maple, " dasycarpum. 

White Elm, Ulmus Americana. Upper district. 

Slippery Elm, " fulva. 

Water Elm, " alata. Alluvial, wet soil. 

American Linden, Tilia Americana. Central to upper district. 

Sycamore, Plantanus occidentalis. 

Cottonwood, Populus monilifera. 

From Robert W. Furnas, Secretary of the Nebraska State Board 
of Agriculture. 

Nebraska State Board of Agriculture, 
.Brownville, Nebraska, January 27, 1892. 

Edwin J. Houston, Esq., 

1809 Spring Garden Street, Philadelphia, Pa. 

Dear Sir, — Reply to yours, First, twenty-third. Of the more 
valuable hard-wood varieties of timber used for forestry pur- 
poses on our prairies, or naturally timberless region, we find 
the best, — black walnut, white ash, black and honey locust, 
black cherry, Kentucky coffee-tree, hard maple, burr and 
white oaks. 

Of the soft woods, — soft maple, box elder, cottonwood, and 
the catalpas, — speciosa, and Tea's hybrid. 

Evergreens : red cedar, Scotch, Australian, and white pines. 
Both American and European larch do well. 
If I can serve the forestry cause in any way, command me. 

Truly, 

Robert W. Furnas. 
19* 



222 APPENDIX. 

From Professor M. G. Kern, Editor of Coleman's Rural World* 

St. Lotjis, January 26, 1892. 

Edwin J. Houston, Esq., Philadelphia, Pa. 

Dear Sir, — Your favor of the twenty-third inst. received. 

Kindly excuse a few remarks on Western forestry, rather 
outside of the list of available trees requested. But a part of 
Missouri is heavily timbered, and in these sections the great 
object of the population is to get rid of the timber for money 
or for agricultural purposes. Many portions of the State are 
cleared to the same extent as the older States, with abundance 
of forest supplies for present use. Part of the State is prairie, 
in which the need of timber culture is as great as in all open 
plains. South of us is Arkansas, a mountainous native forest ; 
west, Kansas, Nebraska, and North Iowa, with her endless 
prairies. A wide field, indeed, for forest management, reforest- 
ing, and timber culture. The soil brings forth, mostly with 
rapid growth, all the indigenous species of our forests ; a list 
of such could be valuable only in ratio to the value of the 
timber grown. 

Fast-growing soft woods are considered in wooded sections 
as of little value, scarcely worth planting on a large scale. 
They are generally planted for shelter, ornament, or quick 
shade. No line of difference as to hardiness can in reality be 
drawn, though variety of conditions make certain kinds more 
suitable to certain localities: we differ in this respect from 
more northern latitudes. 

The question of reforesting denuded sections has thus far 
attracted but little public attention. Intelligent husbandry 
steadily advancing, is gradually awaking to the necessity of 
reforestation and the protection of native forests. The pros- 



APPENDIX. 223 

pective value of economic timber is realized by many, and 
the growth of young native timber is encouraged by the usual 
means of protection from cattle and disastrous fires. 

Systematic forest culture, for which there is so boundless a 
field, has thus far been practised to but small extent, though 
every intelligent citizen knows that the most valuable kinds 
of timber are being exhausted very fast. How long this spell 
of popular indifference will last cannot be foretold by the 
wisest. Millions of acres in the lowlands and on hill-sides 
capable of producing the most valuable timbers, lie idle as 
though belonging to some Indian tribe. 

Much popular education is surely needed to break the bar- 
riers of indifference and popular selfishness underlying all the 
evil. We need a tow-line attached to the dormant intelligence 
of the people (as far as American forestry is concerned), to 
draw it into action. When once aroused from the dream of 
inexhaustible forest wealth, the West will do its honest share 
in forest culture, as her resources are almost without limit. 

My most sincere wishes for the success of your forthcoming 
work on Forestry. Command my services at any time when 
special features of information from this section are desired. 

Very respectfully, 

M. G. Kern. 

TREES PRINCIPALLY GROWN IN FOREST CULT- 
URE IN MISSOURI AND ADJOINING SECTIONS. 

Initial Step in Forest Culture. 
Cotton-wood. 
Black Walnut. 
Soft Maple. 



224 APPENDIX. 

Box Elder. 

White American Ash. 

Sugar Maple (to some extent). 
Second Step. 

The introduction of Catalpa species. At present the 
aboye with Black Walnut and White Ash are the leading trees. 

Worthy of extensive culture, though sparsely planted thus 
far, are : 

Tulip-Tree (Yellow Poplar). 

The leading White Oak species. 

White Oak. 

Over-cup Oak. 

Burr Oak. 

Post Oak. 

White Hickory (under certain conditions). 

Of Conifers. 

Bald Cypress (for alluvial lowlands). 

Eed Cedar, for limestone uplands and stony slopes. 

White Pine, especially suited for sandstone formations 
found in sections of Southwestern Missouri and Arkansas. 
Ornamental trees of this species, met everywhere, show re- 
markable vigor of growth and adaptation to the formation. 

Black Cherry (to be recommended for general culture). 

European Alder, for moist and loamy soils, of rapid 
growth, and valuable wood. One of the best of temporary 
nursery trees for larger plantations. 

Soft Woods. 
Soft Maple. 
Box Elder. 
Birch (both nigre and lenta). 



APPENDIX. 225 

Willows. 
Poplars. 

Plantanus, Elms, Sycamore, for various purposes of shade, 
shelter, and wind-breaks. 

Evergreens. 

American White Spruce deserves far more attention than 
thus far enjoyed. It is the most lasting of all spruces. 

Norway Spruce. 

Scotch and Austrian Pine are valuable for close planta- 
tions for shelter. They are, however, deficient as to longevity, 
losing their vigor much sooner than the native American 
species. 

European Larch is suited to the northern parts of 
Missouri, Iowa, and farther north. 

University of Pennsylvania, 
Philadelphia, Pa., February 27, 1892. ; 

Prof. Edwin J. Houston, 

1809 Spring Garden Street, Philadelphia, Pa. 
My dear Professor, — I am in receipt of your favor of 

the 20th inst., and I take pleasure in sending you a list of 

trees suitable for planting in the Southwestern States and 

California. 

Betula occidentalis, Hook. Black Birch. For ornamental pur- 
poses, grows ten to twenty feet high. 

Quercus undulata, Torr. Oak. Four varieties, valuable for 
timber and for masting, furnishing, as they do, an abun- 
dance of sweet, edible acorns. 

Salix cordata, Muhl., var. vestita, Anders, Diamond Willow, 
abundant in Yellowstone regions, valuable for furnishing 
unique canes. 
P 



226 APPENDIX. 

Salix purpurea, L. Purple Willow, six to fifteen feet. Best of 
hedge and osier willows. Correspond with United States 
Department of Agriculture concerning. 

Salix lucida, Muhl. Shining Willow, five to ten feet. One of 
the most beautiful willows for ornamental planting. 

Salix fragilis, L. Brittle Willow, Crack Willow, Bedford Wil- 
low, sixty to eighty feet, affords best willow timber, and 
contains large per cent, of tannin, and more salicin than 
others. 

Salix alba, L., vars. Salix cseruea and Salix Vitellina, Blue 
Willow, and Golden Willow. Particularly useful as os- 
sier or basket-making willows. 

Populus nigra, Black Poplar, thirty to forty feet, of rapid 
growth, wood valuable for flooring, cooperage, and for 
gunpowder charcoal. 

Populus tremuloides, Mx. American Aspen, " Quaking Asp," 
twenty to fifty feet. 

Populus nigra, var. dilatata, Lombardy Poplar, tall, spire- 
shaped tree, of rapid growth, to be set in rows for wind- 
breaks. 

Populus monilifera, Ait. Necklace Poplar, large tree, one 
hundred and fifty feet high, light, soft wood, useful for 
box manufacture, and especially for paper pulp. 

Juniperus Virginiana, L. North American Red Cedar, or Pencil 
Cedar. The largest of American junipers, sixty to ninety 
feet, furnishes a light, fragrant, and imperishable wood. 

Abies concolor, Small Balsam Fir, or White Fir, eighty to one 
hundred feet. 

Abies nobilis, 

Abies magnifica, 



\ Red Fir. 



APPENDIX. 227 

Abies religiosa, the Sacred Fir of Mexico. 
" bracteata, one hundred feet. 
" Canadensis, Mx. Common Hemlock, fifty to eighty feet. 

Pseudotsuga Douglasii, Can. Douglas Spruce, one hundred 
and fifty to three hundred feet. 

Picea Engelmanni, Eng. Spruce, sixty to one hundred feet. 
" pungens, Eng. Balsam Spruce, sixty to one hundred feet. 

Pinus fiexilis, James. Pine, sixty feet. 

Pinus ponderosa, Dougl. var. Scrophulorum, Eng. Yellow 
Pine, eighty to one hundred feet. 

Salisburia adiantifolia (or Ginkgo biloba), forty to eighty feet. 

Pinus edulis, Eng. The Pifion or Nut Pine, ten to fifteen feet. 

Sequoya sempervicens, Sequoya gigantea, Red Wood, two hun- 
dred to three hundred feet, wood almost imperishable. 
Both these trees should be planted, as they are likely to 
become extinct unless rescued by cultivation. 

Eucalyptus globulus, Blue Gum, peculiarly valuable in swampy 
or malarial districts. One hundred and fifty varieties of 
Eucalyptus, " the tree of the future." Of. article in Pop. 
Sci. Mo., vol. xii. : " The Eucalyptus of the Future," by 
Samuel Lockwood. See also, below, list by W. S. Lyon. 

Eugenia jambos, Rose Apple, or Jamrosade, twenty to thirty 
feet, should be cultivated in the Southern States for its 
delicious fruit. 

Gatalpa bignonioides, Walt. Catalpa, thirty to fifty feet, a beau- 
tiful tree, possessing great advantages for timber, being 
the cheapest and easiest grown of all our forest trees, 
native or introduced, and also the most rapid in its growth. 

Paulownia imperialis, Siebold. A grand flowering-tree, forty 
feet high, with immense leaves, of rapid growth, and par- 



228 APPENDIX. 

ticularly suited for parks, road-sides, and shade (from 
Japan), has large, purple, fragrant pannicles of flowers in 
the spring. 

Schinus molle, the Pepper-Tree, or Peruvian Mastich-Tree. 
The leaves exude an oily fluid, filling the air with fra- 
grance, particularly after a rain. 

Eriobotrya japonica, the Loquat, or Mespilus, should be intro- 
duced into the Southern States, being one of the most 
grateful acid summer fruits. The tree is a very hand- 
some, broad-leaved evergreen. 

Cinnamomum camphora, the common Camphor-Tree of China. 
Growing trees can be had at the Agricultural Department, 
Washington, D. C. 

Dryobalanopos aromatica, the Sumatra Camphor-Tree. Both 
of these should be introduced and cultivated in Cali- 
fornia. 

Aleurites triloba, Candle-Nut-Tree, thirty feet, native of the 
Pacific islands, exceedingly useful for its oily nuts. 

Ceratonia Siliqua, the Carob, or St. John's-Bread-Tree. Could 
easily be cultivated in immense numbers from seed, as is 
our ordinary locust-tree, and would be a valuable addition 
to the country, as it would furnish a large amount of 
food for cattle, the bread-bean pods being used for 
feeding cattle and swine in all countries where the trees 
grow, and is being imported largely into Europe and 
England. 

Blighia sapida, the Akee. A native of West Africa, but be- 
coming widely dispersed, would grow in the more South- 
ern States, and furnishes a valuable fruit, very whole- 
some when cooked. 



APPENDIX. 229 

Per sea gratissima, or Alvocada Pear, or Alligator Pear, a small 
tree, bearing large, purplish, pear- shaped fruits, much es- 
teemed for dessert. Would be a valuable addition to the 
fruits of Southern California. 

Prunus amygdalus, the Almond, fifteen feet. Already culti- 
vated in California. 

Carya olivce/ormis, N. Pecan Nut. Is proving one of the 
most valuable trees of Texas; recently introduced into 
Georgia ; the yield of nuts is large, bringing good prices. 

Castanea vesca, Spanish Chestnut. The tree furnishes a large 
percentage of the food of the poorer classes of Southern 
Europe, and its cultivation in this country should be en- 
couraged. A Japanese " Giant" variety has been lately 
introduced. Said to be of better flavor than the Spanish 
chestnut. 

Juglans regia, English Walnut, or Madeira Nut, sixty feet, 
valuable both for its wood and its nuts ; the yield is large, 
as many as twenty-five thousand nuts to a tree. 

Morus alba, White Mulberry, the most valuable for feeding 
silk-worms. Its cultivation should be encouraged. Sev- 
eral varieties are offered by the nursery-men for the large 
edible fruit. 

Achras sapota, the Sapodilla, or Naseberry, a very sweet, high- 
flavored fruit. Tree spreading, with fine, glossy leaves. 

JEgle marmelos, the Bael-fruit, Elephant Apple, Maredoo, or 
Bengal Quince, a small tree, of the orange family, pro- 
ducing an odd fruit and trifoliate leaves. 

Anacardium occidentale, the Cashew-nut. A tree of the Tere- 
binth family, attaining considerable size, and in growth 
resembling the walnut. The curious fruit is kidney-shaped, 
20 



230 APPENDIX. 

about an inch long, and after roasting is a good substitute 
for almonds, etc., at table. 

Anona cherimolia, the Cherimoya, or Jamaica Apple, a loose, 
spreading tree of the Custon Apple family, attaining a 
height of twenty to twenty-five feet. The light-green 
fruit is beautiful, delicious, and considered one of the 
finest fruits of the world. 

Anona muricata, Sour-Sop, fifteen to twenty feet high, fine 
glossy foliage, fruit large, heart-shaped (six to nine inches 
in circumference), green and prickly, contains a fresh, 
agreeable, sub-acid juice. 

Chrysophyllum cainito, the Star Apple. A tree of thirty to forty 
feet, spreading branches, beautifully veined leaves, silvery 
white on the under-side, fruit about the size of an apple, 
wholesome, with an agreeable sweet flavor. 

fficus carica, Fig. Very easy of cultivation, and offered by 
the nursery-men in several varieties; should be largely 
cultivated in California and all our Southern States. 

Malpighia glabra, Barbadoes Cherry. One of the favorite 
trees of the Barbadoes and West Indies, usually planted 
near dwellings, and as hedges. The trees are beautiful 
evergreens, bearing cherry-like fruit of a pleasant taste. 

Mammea Americana, the Mammea Apple, or St. Domingo 
Apricot, sixty to seventy feet high, with broad, ovate, 
shining leaves ; fruit angular, size of cocoanut, with juicy 
yellow pulp of delicious flavor. 

Mangifera Indica, the Mango. This delightful fruit is now 
being introduced largely into Florida. It is of very 
rapid growth and fine form; five or six varieties are 
offered by nursery-men. 



APPENDIX. 231 

See " Popular Science," 1879, for an account of the ameliora- 
tion of climate in dry barren districts by this tree. 

Psidium Cattleyanum, the Cattley or Strawberry Guaya, now 
being much cultivated in Florida, is of fine appearance, 
and the plum-like, claret-colored-rruit being of most 
agreeable flavor. 

Punica granatum, the Pomegranate. Easily grown and very 
handsome ; small trees, flowers showy. One of the most 
desirable fruits. Bark of the tree used in medicine. 

Psidium Guaiava, the ordinary Guava. One of the most valua- 
ble fruits for jellies and preserving. Several varieties 
offered by nursery-men. 

Tamarindus Indica, the Tamarind. A beautiful tree with deli- 
cate blossoms, and soft, pinnately divided leaves, grows to 
eighty feet in height. The pods pressed in syrup or sugar 
form the preserved tamarind of commerce. 

Zizyphus jujuba, the Jujuba. A small tree of the Buckthorn 
family, bearing small yellow, farinaceous, delicious berries. 
The lotus spoken of by Pliny as furnishing the food of 
the ancient Lybian people called Lotophagi. 

Melia azedarach, L. The Bead-Tree, or Pride of India. Beau- 
tiful for streets and parks of our Southern cities ; thirty to 
forty feet high, flowers fine, loose, terminal, lilac-like spikes. 

Dichopsis gutta. The Gutta-percha. This is a tree of the 
Star-apple family, attaining a height of from sixty to 
seventy feet. Leaves smooth, ovate, rusty-brown on un- 
der-side. This valuable tree is rapidly becoming extinct 
in its native habitations, and efforts should be made to 
introduce it into all tropical and subtropical climates. 
The French government has recently decided to cultivate 



232 APPENDIX. 

it in Algeria. Why should it not be introduced into 
Southern California? 
Mimusops globosa. The Ballata. Furnishes a milky juice 
equal to the best gutta-percha of the East. This should 
be tried. It is a native of British Guiana. 
Butyrospermum Parkii, the Karite or Butter-Tree. An African 
tree, furnishing from its seeds the Shea-butter of com- 
merce, used in soap-making, and a gum or coagulated 
juice which has recently been found to be equal to the 
best gutta-percha. It is possible that this tree might be 
made to grow in the warmer parts of California. 
Cinchona calisaya, Cinchona succirubra, Cinchona condaminea. 
These three species of cinchona have been successfully 
cultivated in Mexico ; in the Canton of Cordova several 
thousand cinchona-trees exist and are doing well. The 
beautiful trees with large velvety leaves, turning red when 
old, may be seen by those who travel by rail from Vera 
Cruz to Mexico. It is worthy of serious effort to cultivate 
this valuable tree in Texas and California. 
Quillaja saponacia, Quillaia-bark Tree, Soap-bark Tree. This 
large tree (fifty to sixty feet) yields in its bark a product 
very valuable in- cleaning delicate colored fabrics, and 
could undoubtedly be grown with profit in California. 
The sub-tropical trees mentioned in the above list can all 
be obtained from the nursery-men {e.g., Siebrecht & Wadley, 
Eose-Hill Nurseries, New Eochelle, New York), or of the 
Agricultural Bureau, Washington, D. C, and they can be 
successfully grown in any of the Southern States where 
the winter temperature does not fall below 45° F. I have 
not mentioned many well-known varieties, but have preferred 



APPENDIX. 233 

to call attention to such little-known trees as might perhaps be 

cultivated (and, in fact, are already to some extent in Florida 

and California) successfully, with profit in various ways to our 

Southern States. 

Very respectfully yours, 

C. S. DOLLEY. 

State Board of Forestry, 
Los Angeles, California, June 6, 1892. 

Prof. Edwin J. Houston, 

1809 Spring Garden St., Philadelphia, Pa. 
Dear Sir, — I send you a few "notes." The second part 
will deal with the much larger subject of lands outside of the 
natural forest districts, suitable only for forest planting, and 
the species we find most useful thereon. Our experiments 
with these are practicable and tangible, and I trust will prove 
of more value than the " glittering generalities" of the accom- 
panying Part I. 

I will endeavor within a week to give you the balance. 

Veiy truly yours, 

Wm. S. Lyon. 



NOTES. 

PART I. 

ON TREES SUITABLE FOR REFORESTATION UPON THE 

PACIFIC COAST. 

There are portions of the Sierra Nevada Mountains which, 
by the various processes of surface-mining, have been denuded 
of their original forest cover, as well as of every vestige of 
forest floor, — i. e., fertile soil. 

20* 



234 APPENDIX. 

In many localities the areas laid bare amount to hundreds 
of acres in single tracts. 

In portions of Amador and Calaveras Gounties, multitudes 
of "prospects" join each other, extending for miles upon a 
so-called " river-bar." 

These " prospects" are frequently only holes that have been 
excavated from four to ten feet in depth, and the auriferous 
gravel thrown out and scattered far enough to nearly com- 
pletely cover the original surface soil for from one to ten inches. 

In Placer and Nevada Counties the process of hydraulic 
mining has generally washed out vast flats or valleys in the 
mountains, and leaving the resulting basin covered chiefly 
with gravel, boulders, or blue clay. 

These operations have been discontinued in some localities 
for now more than thirty years ; in others, only recently. 

Yet in all of them, and apparently with an utter dearth of 
soil, the native timber is making an effort to assert itself. 

At Dutch Flat, where gigantic mining operations have only 
ceased during three years, a very sparse setting of small 
Psuedotsuga Dougiasii, Pinus tuberculata, Libdocedrus decurrens, 
and Pinus Sabinana have established themselves. The same 
features exist upon the Mokelumne River, in Calaveras County, 
where no mechanical disturbance has occurred since the 
original covering up of the soil thirty years before. 

Both localities are between three thousand and three thou- 
sand six hundred feet in elevation, and the timber is such as 
belongs to that elevation in the Sierras. 

The uninjured timber in the more southern county and 
adjoining denuded lands, can only be described as scrubby; 
and 1 cannot say that that which has established itself upon 



APPENDIX. 235 

the worked-over sites has been notably depauperized by its 
mulch of clay and gravel. At the point of southern observa- 
tion Abies concolor occurs, and seems to thrive. 

I noted with interest that young plants of the Douglas 
spruce, growing about denuded fields in Nevada County, at 
three thousand five hundred feet, showed great vigor, although 
naturally fine specimens (mature) seldom occur in the prim- 
itive forest below five thousand feet. 

It occurs to me that this is an index that this plant may 
prove valuable for future systematic reforestation. The other 
species named, except for purposes of forest cover, are not 
held in much esteem by lumbermen. At higher altitudes, and 
in the regions covering our valuable pines and spruces, extend- 
ing over nearly seven hundred miles from San Bernardino to 
Plumas County, no mining operations (surface) have been 
conducted, and, except in isolated cases of torrential erosions, 
the forest floor is intact. 

The original cover has been, however, heavily cut and 
burned over. Their native reproductive powers seem in- 
destructible. 

Where deforestation has been caused by the axe, a fall 
proportion of young growths of Pinus lambertiana, P. Coulteri, 
P. Jeffreyi. P. ponderosa, and PsuedoUuga Douglasii seem to 
follow. 

Where the denudation has occurred from fire, the more 
relatively worthless White Fir, Flat-leaved Cedar, and Hem- 
lock seem to preponderate. 

In the mountains, — i. e., the natural timber district of the 
State, — not a single instance occurs where reforestation, upon 
any scale, large or small, has been undertaken. 



236 APPENDIX. 

No attempt or experiment with exotic species has ever been 
tried within the timber belt, and the values of the endemic 
species, and their readiness to conform to such unpromising 
situations as those described, justify us in thinking that they 
will best fulfil future systematic mountain reforestation. 

PART II. 

SPECIES USEFUL FOR REFORESTATION OF FOOT-HILL-LANDS, 
WASHES, OR LANDS UNSUITABLE FOR GENERAL AGRI- 
CULTURE in California. 

(A) Endemic Species. 

First among them I rate the Pinus insignis, or Monterey 
Pine. Naturally restricted to a narrow strip of land upon the 
Mid- California seaboard, not extending inland more than ten 
miles, it has taken kindly to transplantation to the interior 
hotter, drier valleys for more than one hundred miles from 
the sea. It rarely exceeds a height of thirty metres ; the tim- 
ber is generally twisted, coarse in grain, deficient in strength, 
not durable, and rates low for either lumber or fuel uses. Its 
pre-eminent value is as a forest cover and wide adaptability to 
soil and climate. 

Extensive plantations upon arid, gravelly hill-sides, without 
care or cultivation, have attained an average height of twelve 
feet in five years from the seed, and isolated specimens have 
made a growth of sixteen feet during that time. It resists 
fire well, young plantations where badly burned over — i.e., with 
three-quarters of the foliage destroyed — generally recuperating. 

Cupressus macrocarpa, a smaller tree, fifty to seventy feet, 
nearly as local as the Pinus insignis, of still more rapid devel- 



APPENDIX. 237 

opment, of more widely-tried distribution, and adapted to soils 
lacking in fertility ; thrives wherever our rainfall reaches an 
average of sixteen inches, and resists extreme summer heat 
well ; holds its lower branches and foliage with tenacity to a 
great age, making it serviceable for wind-breaks or ornamental 
hedging; the wood is light, but extremely durable under- 
ground, making it valuable for posts. Its small size makes it 
unavailable for general lumbering uses, other than as a cabinet 
wood, for which it is well adapted. 

These two are the only native conifers that have been suc- 
cessfully planted upon lands deficient in moisture and fertility, 
upon a scale, and over a period of time prolonged enough, to 
assert that they will prove valuable for our so-called arid 
hill-sides. 

In a more experimental way, upon more restricted areas, 
away from their native habitats, the subjoined coniferous spe- 
cies have been planted, and success has only followed where 
the soil was of reasonable depth, fair fertility, and where water 
was not remote from the surface. Such plantations have 
proven successful in the northern part of the State where water 
surface was distant, but only where the average annual rain- 
fall exceeds twenty inches, and where the plantations have 
been made in nooks and valleys sheltered from drying winds. 

In the southern half of the State, these conditions are not 
sufficient, and a deeply- cut, well-sheltered, canon canying 
water upon or near the surface is a sine qua non. 

The species are : 

Sequoia sempervirens. 

Sequoia gigantea. 

Chamcecyparis Laiosoniana. 



238 APPENDIX. 

All these are species reaching heroic dimensions, and the 
first and last rank in the very first class as unsurpassed timber 
trees. 

The limits of their utility for forest planting is, owing to the 
conditions stated above, restricted to very narrow limits. 

Pinus Sabiniana and Juniperus California both extend into 
the lower foot-hills, and naturally occur upon barren, stony 
lands of poorest quality ; and though nothing more than occa- 
sional experimental tests have been made, no question or 
doubt as to their utility upon utterly waste lands exists. 

Their relatively slower growth, and inferior fuel and timber 
value, to the Monterey pine and Monterey cypress, explain 
their neglect, rather than any doubt as to their successful 
development. 

For points where the conditions of soil and climate discour- 
age the planting of the latter, these two species can be success- 
fully introduced. 

Of our native oaks, occasional tests have been made with a 
few species. The most valuable, the Quercus densiflora, makes 
but poor growth outside of humid and elevated ravines. Quer- 
cus lobata demands soil of both depth and fertility. Under 
these conditions it makes phenomenal growth. I have cut a 
tree displaying but forty-five annular rings, that measured four 
feet ten inches in diameter above any buttress. 

Quercus agrifolia has proven most tractable of all upon dry, 
stony sites. Transplants easily, and after establishment makes 
fairly rapid growth. Its rather small size is an objection. The 
timber is inferior, stands but little transverse strain, but yields 
a superior fuel. 

With our other trees no transplantations other than orna- 



APPENDIX. 239 

mental have been made of those extending below the conif- 
erous timber belt. 

Chief among them, the Oregon ash, Oregon maple, syca- 
more, cotton-wood, and laurel occur mostly in canons, and 
with the exceptions noted are unsuitable for general planting. 

The cotton-wood, Populus Fremontii, has shown (on a large 
scale) conformability to the lands strongly alkaline. Such are 
waste lands for this purpose, as the process of reclamation is 
tedious and costly. They comprise many thousands of acres 
of our West Coast bottoms, and no tree outside of this cotton- 
wood and Tamarix gallica (exotic) that has been tested upon 
them has heretofore proven satisfactory. Growth quick ; timber 
warps badly ; rates low for fuel. 

The Laurel, Umbellularia Californica, has been attempted 
away from water-courses, with some measure of success. The 
timber is invaluable for veneers, exceedingly hard and heavy, 
and excels the cherry and redwood burl in beauty, but is of 
such exceedingly slow growth that few attempts have been 
made looking to its extended planting. 

PART III. 

(B) Exotic Species. 

Considerable plantations have been made throughout the 
State with Eucalyptus species. 

These in size range from one to four hundred acres. Plan- 
tations have been made with some fifty species, but ninety per 
cent, embrace, — 

No. 1, Eucalyptus globulus. 

Nine per cent, are of 

No. 2, Eucalyptus rostrata, and 



240 APPENDIX. 

No. 3, Eucalyptus virinalis, and less than one per cent, of 
the other species. 

No. 1, by reason of its more rapid growth, has been most 
freely planted. It is confined to the thermal belt, suffering 
when young from low temperatures (2° to 4° F. of frost). 
Nos. 2 and 3 are much hardier, and are equally resistant of 
drought. 

All will grow upon arid hills, but only make remunerative 
growth where the subsoil is of an open, porous nature ; the 
root must have an opportunity to get down. Upon rock or 
impervious subsoils these three gums may be seen, fairly 
vigorous, but not averaging over twelve to fifteen feet, now 
with stem diameter of over two and a half inches, representing 
five and six years' growth. Eesults about equal to one year 
upon open, porous soils of fair quality. 

In value for fuel or timber, they take precedence as 
follows : 

E. rostrata, 1. 

" globulus, 2. 

" virinalis, 3. 

The former is reputed to be " teredo"-proof ; but there is 
no timber as yet within the State large enough for wharf 
purposes. 

In a smaller way, tests have been made with other species ; 
the following prove of greatest merit : 

Euc. corynocalyx (Sugar Gum). Hard and durable timber. 
Tree umbrageous, endures drought and sterile soils. Suscepti- 
ble to light frosts. 

Euc. diversicolor, characteristics not dissimilar from last. 

Euc. populi folia, smaller tree than last, but hardier. 



APPENDIX. 241 

Euc. leucoxylon, rose-flowered variety, and 

Euc. amygdalina, var. angustifolia, are the only two species 
that extend beyond our extra-tropical limits, having success- 
fully withstood the cold of 16° F. 

Have not seen the E. amygdalina tested upon poor soils. 
The former, however, is very tenacious of life upon dry and 
poor lands. 

Both make trees of the greatest magnitude. 

In cultivable lands, Euc. Gunni will make more rapid growth 
than E. globulus, and hence is profitable for a fuel crop that 
can be cut every four years. 

A few other promising sorts are, — 

E. citriodora, for its essential oil. Dry exposures. 

E. paniculata. Dry exposures. 

E. punctata. Dry exposures. 

Most species of Eucalypti make good fuel ; a few are very 
durable under ground or in water, and though largely used 
in the antipodes for railway building, ties, etc., are in dis- 
repute here from the tendency of some species to check and 
warp, disabilities that can be overcome by cutting in proper 
season and reasonable attempts at curing. 

Acacias. 

Upon any soil non-alkaline, and wherever the rainfall ap- 
proximates sixteen inches, these are indicated for general 
forest uses. 

They require but little assistance to be established, attain 
marketable size in five to eight years, furnish an excellent fuel 
(wood too small for most economic purposes), and some excel 
all other trees in the quantity and quality of superior tan- 
bark yielded to the acre. They have been fairly tested upon 
l q 21 



242 APPENDIX. 

hill, valley, and brush lands, where cultivation was impracti- 
cable; the results have been promising, although, like the 
eucalypti, a measurable and perhaps profitable increment in 
growth has followed the cost of cultivation. 

The most valuable species — i.e., the one richest in tannin — is 
the Acacia pycnantha. It is, however, more sensitive to cold 
than some others, and hence properly restricted to the thermal 
section of the coast. 

The next in value. A. decurrens, and its immediate congener, 
A. moligsima, are suitable for a very wide range, thriving in 
the littoral regions, as well as for one hundred miles inland, 
and for a length of seven hundred miles north and south. 

A. melanoxylon is less valuable for its tan-bark, but makes a 
larger tree (twenty metres), and furnishes a valuable cooper's 
wood and the best fuel. It requires, perhaps, more moisture 
and a better soil than the other species to obtain its maximum 
growth. Incidentally it is compact and symmetrical in habit, 
hence serving well for wind-breaks or street-planting. 

Casuarinas of different sorts have been fairly tried. Among 
them C. stricta, C. teniusimus, C. suberosa, and C. equisitacetolia. 
All are rapid growers and hardy, also adapted to arid sites. 

The last-named has given larger evidence of versatile adapt- 
ability to our requirements of soil and climate. 

Allied to the acacias we have a tree of phenomenally rapid 
growth, and conformable to waste lands. It is Albizzia lo- 
phantha. It is of no possible economic value except for the 
marvellous rapidity with which it furnishes forest cover, and 
is thus rendered available for furnishing a quick and short- 
lived protection to coniferous plantations. 

Eastern United States Silva have been but sparingly at- 



APPENDIX. 243 

tempted. Eeasonable success has followed the planting of 
both Catalpa and Robina psuedo Acacia in the northern half 
of the State. In the south they exigently demand soil of 
greater depth and fertility than we are willing to classify as 
forest lands. The same holds true of most of the nut-bearers, 
the Caryas and allies, although sporadic and unprofitable 
attempts have been made with the English, the Black Walnut, 
and the pistachio. 

Some plantations of Finns pinaster give promise of doing 
well, remote from the seaboard, and, to a limited extent, P. 
Austriaca, P. strobus, P. cembra, and P. Laricio have been 
planted. 

Eesults, as far as obtained, indicate unsatisfactory growth, 
although the limited period of observation makes it premature 
to formulate any conclusions. 

Isolated cases exist of above fifty additional exotic species 
that have been planted for forest uses. 

The data is sufficient to furnish material that is not largely 
hypothetical. 

If such be desired, a synoptical list can be supplied. 

William S. Lyon. 



INDEX. 



Agricultural districts, necessity for 
preservation of trees in, 14, 15. 

Agriculture, demands of, for re- 
moval of forests, 11. 

Aims of forestry, 10. 

Air, changes in composition of, ef- 
fects of, on earth's life, 166, 167. 

Alps of Provence, Marsh on, 115, 
116. 

Amazon, forest lands of, 28. 

Animal and vegetable kingdoms, 
wonderful balance in the compo- 
sition of the atmosphere insured 
by, 142. 

Animals, minerals and plants, mu- 
tual interdependence between, 
168. 

Animals, necessity for oxygen in 
respiration of, 141. 

Animate enemies of the forest, 64, 
71 to 76. 

Annual Report of New York For- 
estry Commission, extract from, 
18, 19. 

Assimilation, definition of, 22. 

Atmosphere, composition of, 140. 
different composition of, in ge- 
ological past, 143, 144. 
heat received from the heated 

earth, 119. 
heat received from the sun by 
absorption, 119. 



Atmosphere, manner in which it 
receives heat from the sun, 
119. 
possible danger from disturb- 
ance of composition of, by 
removal of forests, 144, 145. 
purification of, 140 to 145. 
Avalanche, influence of, in destruc- 
tion of forests, 67. 
Axe of pioneer, a badly-chosen 
emblem of civilization, 85. 

B. 

Balance of nature, 164 to 173. 
Bannwoelder, 67, 68. 
Basin of river, definition of, 111. 
Beavers, destruction of forests by, 

73. 
Beech plum, story of, 35, 36. 
Beetles, destruction of forests by, 75. 

C. 

Calcareous soils, definition of, 51. 
Carbonic acid, decomposition of, in 
plants by sunshine, 22. 

influence of, on growth of 
plants, 22. 

influence of, when dis- 
solved in water, in dis- 
integration of rocks, 55. 

necessity of, for existence 
of plants, 142. 

of atmosphere, use of, 140. 



21* 



245 



246 



INDEX. 



Carboniferous period, composition 

of the atmosphere during, 144. 
Caterpillars, destruction of forests 

by, 73, 74. 
Cause of deserts, 42. 

of meadows and prairies, 43. 
of steppe regions, 43. 
Classes of land suitable for main- 
tenance of forests, 158, 159. 
Clayey soils, definition of, 50, 51. 
Climate, definition of, 119. 

influence of elevation of land 

on, 121, 122. 
influence of land and water 

areas on, 120, 121. 
influence of the presence of 

the forest on, 127 to 133. 
influences producing variations 

in, 120, 121, 122. 
of forest region, characteristics 

of, 124. 
peculiarities of continental, 123. 
peculiarities of oceanic, 123. 
Comparative unimportance of soil 

for plant growth, 25. 
Conditions influencing the rapidity 
of spread of forest fires, 65, 
66. 
necessary for the growth of 

plants, 20 to 24. 
necessary for the growth of 

trees, 42 to 47. 
required for the production of 
rain, 101. 
Continental climate, peculiarities 
of, 123. 

D. 

Dana, James D., extract from his 
" Manual of Geology," 70, 145, 
146. 



Decaying leaves, influence of, on 

disintegration of rocks, 57. 
Decomposition of carbonic acid in 

plants by sunshine, 22. 
Definition of assimilation, 32. 

of forestry, 9. 
Deforestation and reforestation, 14. 
Deserts, cause of, 42. 
Destruction of forests, 81 to 86. 
by fire, 64, 65, 66. 
evil results following, 
81, 82. 
Disintegration of rocks, agencies 

causing, 52, 53. 
Distant planets, possibilities as to 
the existence of life thereon, 98. 
Distinctive flora of particular re- 
gions, meaning of, 30. 
Distribution of heat, influence of, 
by destruction of forests, 84. 
of solar energy, how affected, 
170, 171. 
Domestic and domesticated plant 

species, 33. 
Drainage, 109 to 113. 
definition of, 109. 
influence of mountains on, 16. 
surface, definition of, 110. 
underground, definition of, 110. 
Droughts, caused by destruction of 
forests, 81. 

£. 

Earth's ocean of vapor, 90 to 97. 

Earthworm, influence of, in forma- 
tion of soil, 56. 

Egyptian mummies, reputed pres- 
ervation of plant seeds in, 33. 

Electrical theory of hail, 149, 150 

Equatorial currents of air, why 
rain-bearing, 101. 



INDEX. 



247 



Equatorial land areas, effect of, on 

earth's climate, 166. 
Erosion, definition of, 54. 

influence of, in the formation 
of soil, 53. 
Evaporation, circumstances influ- 
encing rapidity of, 90, 91, 92. 
of moisture, inconstancy of, 
171, 172. 
Excavations, growth of plants on 
exposure of soil brought up by, 
35. 
Excessive multiplication of life, 
how avoided, 169, 170. 

F. 

Feldspathie rocks, elayey soils de- 
rived from, 51. 
Fernow, B. E., definition of for- 
estry, 17. 
Fire, destruction of forests by, 64, 

65, 66. 
Fire-weed, curious conditions re- 
quired for germination of, 37. 
Flammarion, Camille, extract from 

" The Atmosphere," 125, 126. 
Flora, definition of, 26. 

effect of elevation on, 48, 49. 
effects of the distribution of 
heat, light, and moisture on, 
26. 
influence of temperature on, 

31. 
on mountain slopes, why differ- 
ent at different altitudes, 26, 
27. 
Forest, animate enemies of, 64, 71 
to 76. 
areas, intelligent protection of, 
13. 



Forest, climate, characteristics of, 
128. 
fires, conditions influencing the 
rapidity of spread of, 
65, 66. 
how started, 65. 
inanimate enemies of, 61 to 67. 
influence of area on absorption 

of heat, 127. 
influence of forest area on los3 

of heat, 128. 
influence of presence of, on 

climate, 127 to 133. 
lands of the Amazon, 28 
preserves, 14. 
Forestry, aims of, 10. 

associations, field for, 10, 13. 
definition of, 9. 
Fernow's definition of, 17. 
laws, necessity for, 10, 13. 
mistaken ideas concerning, 13. 
Forests, dependence of, on climatic 
conditions, 62. 
. destruction of, 81 to 86. 
by beavers, 73. 
by beetles, 74. 
by caterpillars, 73, 74. 
by goats, 73. 
by grasshoppers, 73, 

74. 
by insects, 73, 74. 
by man, 75, 76. 
by mice, 78. 
by typographer bee- 
tle, 75. 
distribution of heat, influence 

of, by destruction of, 84. 
disturbance of the balance of 
nature affected by removal 
of, 172, 173. 



248 



INDEX. 



Forest, droughts produced by de- 
struction of, 81. 

encroachments on, necessity 
for, 11. 

influence of avalanches in de- 
struction of, 67. 

influence of inundations in 
destruction of, 66. 

influence of, on humidity of 
air, 97. 

influence of, on natural drain- 
age, 113. 

influence of, on preventing 
disastrous frosts, 130, 131. 

influence of, on rapidity of 
evaporation, 97. 

influence of parasitic plants on 
destruction of, 71, 72. 

influence of rodents on destruc- 
tion of, 73. 

influence of torrents on de- 
struction of, 58. 

influence of wind on destruc- 
tion of, 66. 

inundations produced by de- 
struction of, 81. 

loss of soil following destruc- 
tion of, 81. 

malarious diseases produced by 
destruction of, 82. 

natural drainage disturbed by 
destruction of, 82. 

necessity for preservation of 
exact balance of conditions 
to existence of, 63. 

necessity for removal of, 11. 

of mountain slopes, 46. 

influence of, on 
rapidity of 
drainage, 104. 



Forest of tropical regions, 46. 

peculiar distribution of moist- 
ure causing, 43. 
products of, 11. 
protection afforded by, against 

frosts, 129. 
why a regular distribution 
of moisture is requisite for 
growth of, 44, 45. 
why the air of, is cooler and 
damper in summer tban air 
over open fields in same 
district, 132. 
Formation of soil, 50 to 57. 
Freezing and melting of ice, in- 
fluence of, on disintegration of 
rocks, 52, 53. 



G. 

Gases, absorption of, by soils, 56. 
Geikie, Archibald, extract from 
"Text-Book of Geol- 
ogy," 60, 78, 88, 133. 
Germ, necessity for existence of, for 

plant life, 23. 
Germ-cell, protoplasm of, 20. 
Germs of plants, source of, 21. 

wonderful vitality of, 
21, 33, 34, 35, 36. 
of seeds, wonderful vitality of, 
33, 34, 35, 36. 
Glaciers, definition of, 54 

influence of, in formation of 
soil, 54, 59. 
Goats, destruction of the forests by, 

73. 
Grasshoppers, destruction of forests 

by, 73, 74. 
Gravelly soils, definition of, 50. 



INDEX. 



249 



Guyot, Arnold, extract from 
" Earth and Man," 28, 29, 48. 

H. 

Hail, 147 to 152. 

influence of destruction of 
forest on occurrence of, 
147. 
Volta's theory of, 149, 150. 
Hail-rods, 150. 

Hailstones, structural peculiarities 
of, 148. 
varying sizes of, 148, 149. 
Hail-storms, damages caused by, 
151. 
electrical phenomena of, 148. 
rate of the wind during, 
151. 
Hartt, Ch. Fred., extract from 
" The Geology and Physical Ge- 
ography of Brazil," 137, 138. 
Heat and light, necessity of, for 
plant growth, 24. 
energy, disappearance of, on 
evaporation of water, 95. 
liberation of, on conden- 
sation of vapor, 95. 
units, 95. 
Hough, Franklin B., extract from 
"Report on For- 
estry," 76, 77, 78. 
extract from the " Re- 
port of the United 
States Commission- 
ers for 1877," 159 
to 163. 
extract from " Report 
of United States 
Commissioners of 
Forestry," 135, 136. 



Houston, Edwin J., extract from 
"Elements of Physical Geogra- 
phy," 29, 30, 86, 87. 

Humboldt, Alexander von, extract 
from "Cosmos," 99, 104, 105. 

Humidity of air, influence of, on 
evaporation, 92. 

Huxley, T. H., extract from 
"Physiography," 106. 

Hydrogen, in plant tissues, source 
of, 23. 

Hydroscopic properties of soils, 56. 



Inanimate enemies of the forest, 

61 to 67. 
Influence of mountains on drain- 
age, 16. 
Insects, destruction of forests by, 
73, 74. 
larv?e of, destruction of forests 
by, 74. 
Interests of lumbermen and for- 
estry associations mutual, 18. 
Inundations caused by destruction 
of forests, 81, 82, 83. 
causes of, 81, 82, 83, 111, 

112. 
influence of, on destruction of 

forests, 66. 
influence of the surface on the 
number and severity of, 112. 
Island of St. Helena, Lyell on the 
destruction of its forests, 87. 



Jack Sprat, of nursery lore, 143. 
" Journal of the Society of Arts,' 
extract from, 89. 



250 



INDEX. 



L. 

Land and water areas, exact bal- 
ance between, 165. 

Lands suitable for preserving forests 
on, 15. 

Le Conte, Josepb, extract from 
" Elements of Geology," 59. 

Lindley, Jobn, extract from his 
" Botany," 39 to 41. 

Loomis, Elias, extract from " Trea- 
tise on Meteorology," 152, 153. 

Lyell, Charles, extract from " Prin- 
ciples of Geology," 69, 87, 114, 

115. 

M. 

Mackenzie River, raft in, 67. 

Malarious diseases produced by de- 
struction of the forests, 82. 

Man, destruction of forests by, 75, 
76. 

Marsh, George P., extract from 
" The Earth as Modified by Hu- 
man Action," 38, 89, 58, 115, 
116, 173, 174, 175, 176. 

Matter, organic and inorganic, dis- 
tinction between, 29. 

Maury, M. F., extract from " Phys- 
ical Geography," 107, 108. 

Meadows and prairies, peculiar dis- 
tribution of moisture causing, 43. 

Method, nature's, of distributing 
plant germs, 32. 

Mice, destruction of forests by, 78. 

Mineral matters, necessity of, for 
plant growth, 25. 
source of, in plant tissues, 
23. 

Minerals, plants and animals, mu- 
tual interdependence between, 
168. 



Mississippi River, raft in, 67. 

rafts, Lyell on, 69. 
Moist air of forest, influence of, on 

absorption of heat, 130. 
Moisture, effect of variations in 
amount, on character and 
distribution on flora, 42. 
how absorbed by plants, 22. 
of atmosphere, use of, 141. 
principal food of plants, 22. 
Mountain rains, how caused, 102. 
slopes, forests of, 46. 

necessity for preservation 
of forests on, 47. 
Mountains the birthplaces of rivers, 
47, 103, 104. 
the natural home of the forest, 
reasons for, 15, 16, 17. 
. the natural home of the rivers, 
16. 
Mud-flats, damages produced by, 84. 
Mutual interests of forestry associ- 
ations and lumbermen, 18. 

N. 
Natural drainage, damages pro- 
duced by the disturbance 
of, 112. 
disturbed by destruction 
of forests, 82. 
Nature, balance of, 164 to 173. 
Necessity for preservation of for- 
ests on mountain slopes, 47. 
of germs for the existence of 

plants, 23. 
of oxygen for growth of plants, 
23. 
New York Forestry Commission, 
extract from Annual Report of, 
18, 19. 



INDEX. 



251 



Oceanic climate, peculiarities of, 

123. 
Oxygen of atmosphere, use of, 140. 
necessity for, in respiration of 
animals, 141. 



Paragreles, 150. 

Parasitic plants, influence of, in 

destruction of forests, 71, 72. 
Peaty soils, definition of, 51. 
Pine forests, appearance of scrub 

oak on burning over of, 36, 37. 
Plant germs, nature's method of 
distributing, 32. 
wide distribution of, 32 to 

38. 
wonderful vitality of, 33, 
34, 35, 36. 
nationality, 26. 
seeds, wonderful vitality of, 
33, 34, 35, 36. 
Planting of trees, when advisable, 

157. 
Plants, animals, and minerals, mu- 
tual interdependence be- 
tween, 168. 
conditions necessary for the 

growth of, 20 to 24. 
decaying, influence of, in for- 
mation of soil, 50. 
necessity of oxygen for growth 

of, 23. 
source of germs of, 21. 
source of seeds of, 21. 
Polar currents of air, why generally 
drought-producing, 101. 
land areas, effect of, on earth's 
climate, 167. 



Prairies, new growth of plants 
marking wagon-tracks on, 36. 

Precipitation, forms of, 100. 

Pressure of air, influence of, on 
rapidity of evaporation, 92. 

Prestwich, Joseph, extract from 
" Geology, Chemical, Physical, 
and Stratigraphical," 117, 118. 

Products of the forests, 11. 

Protoids, definition of, 29. 

Protoplasm of germ-cell, 20. 

Pouchet, extract from " The Uni- 
verse," 78, 79, 80. 

Purification of the atmosphere, 
140 to 145. 



Railway sleepers, demands on for- 
ests for, 89. 
Rain, 100. 

causes of, 100. 

Huxley on the distribution of, 

106. 
Maury on the distribution of, 
107, 108. 
Rainfall, distribution of, 102. 

true index of the wealth of a 
country, 94. 
Reclus, Elisee, extract from 
"Earth," 67, 68, 69, 
116, 117. 
extract from " Ocean," 30, 
31, 48, 49. 
Red River, raft in, 67. 
Reforestation, 155 to 159. 
and deforestation, 14. 
definition of, 155. 
necessity for government en- 
couragement of, 156. 
objects of, 155, 156. 



252 



INDEX. 



Reforestation of mountains, French 
code for, 159, 160, 161, 162, 
163. 
various methods employed in, 

156. 
when possible, 155, 156. 
Regions, steppe, peculiar distribu- 
tion of moisture causing, 43. 
Reservoirs, definition of, 109. 
River basin, definition of, 111. 
rafts, 67. 

system, definition of, 111. 
Rivers, cause of difference in size 

of, 110. 
Roads, demands of, for removal of 

forests, 11. 
Rocks, agencies causing disintegra- 
tion of, 52, 53. 
crystalline, original source of 

soil of, 50. 
disintegration of, 50. 

influence of solvent 
power of water on, 
54, 55. 
influence of sprouting 
vegetation on, 53. 
influence of layer of decaying 
leaves on disintegration of, 
57. 
Rodents, influence of, on destruc- 
tion of forests, 73. 



Sahara desert, appearance of plants 
on irrigation of, 34. 
wadys in, 34. 
Sand-bars, damages produced by, 

84. 
Sandy soils, definition of, 50, 51. 



Scrub oak, appearance of, on burn- 
ing over of pine forests, 36, 
37. 
Seeding of trees, when advisable, 

157. 
Seeds, circumstances preventing 
germination of, 40, 41. 
vitality of, circumstances in- 
fluencing, 39 to 41. 
Snow, protection afforded ground 

by, against frosts, 129. 
Soil, alternate freezing and thaw- 
ing, influence of, in forma- 
tion of, 54, 55. 
formation of, 50, 51. 
influence of earthworm in for- 
mation of, 56. 
influence of erosion in forma- 
tion of, 54. 
influence of glaciers in forma- 
tion of, 54, 59. 
loss of, following destruction of 

forests, 81, 83, 84. 
necessary gradual formation of, 

56, 57. 
or cradle, necessity of, for plant 

growth, 24. 
vegetable, definition of, 60. 
Soils, calcareous, definition of, 51. 
classification of, 50. 
clayey, definition of, 50, 51. 
distribution of, 51, 52, 53. 
gravelly, definition of, 50. 
hygroscopic properties of, 56. 
influence of color of, on power 

of heat absorption, 56. 
peaty, definition of, 51. 
power possessed by, of absorb- 
ing gases, 56. 
sandy, definition of, 50. 



INDEX. 



253 



Sources of hydrogen in plant tissue, 
23. 
of mineral matters in plant 
tissues, 23. 

Species, domestic and domesticated, 
33. 

Springs, source of water discharged 
by, 109. 

Sprouting vegetation, influence of, 
on disintegration of rocks, 53. 

St. Helena, Lyell on the destruc- 
tion of its forests, 87. 

Struggle for existence in the vege- 
table world, 61. 

Subsoil, definition of, 60. 

Sunshine, influence of, in germina- 
tion of seeds of plants, 21. 

Surface drainage, definition of, 
110. 

Surface, influence of, on rapidity 
of evaporation, 91. 

T. 

Temperature of air, influence of, on 
rapidity of evaporation, 91. 
of equatorial and polar regions, 
how balance is preserved be- 
tween, 164, 165. 
Tree-planting, 155 to 159. 

when advisable, 27. 
Trees, conditions necessary for 

growth of, 42 to 47. 
Tree-sowing, 157. 
Torrents, influence of, on destruc- 
tion of forests, 58. 
Tropical flora, why different from 
temperate or arctic flora, 
26. 
rains, how caused, 102. 
regions, forests of, 46. 



Tropical vegetation, Guyot's de- 
scription of, 28, 29, 30. 
Tyndall, John, extract from " Heat 
as a Mode of Motion," 98, 105, 
134. 
Typographer beetle, destruction of 
forests by, 75. 
Hough on, 76, 77. 

U. 

Underground drainage, definition 
of, 110. 

V. 

Vacuum, influence of, on germina- 
tion of seeds, 40. 
Vapor, earth's ocean of, 90 to 97. 
of air, chilling necessary for 
precipitation of, 
100. 
influence of, on econ- 
omy of the earth, 
93, 94. 
Vegetable fibre, source of carbon 
in, 22. 
mould or humus, 50. 
world, struggle for existence 
in, 61. 
Vegetation, agency of, in prevent- 
ing loss of soil, 88. 
Velocity of wind, influence of, on 

rapidity of evaporation, 92. 
Volta's electrical theory of hail, 
149, 150. 

W. 

"Wadys in the Sahara Desert, 34. 
Water or moisture, necessity of, for 
plant growth, 24. 



22 



254 



INDEX. 



"Water, solvent power of, influence 
of, in disintegration of rocks, 
54, 55. 
vapor, screening influence of, 
on sun's heat, 94. 



Wide distribution of plant germs, 

30 to 38. 
Wind, influence of, in destruction 

of forests, 66. 
Winged seeds, 32. 



THE END. 



LIBRARY OF CONGRESS 



002 818 494 3 




